Category: CBSE

Looking for an easy way to Learning of new elementary english grammar and composition for class 6 answers, Solutions. You have to learn basic English Grammar topics like Tenses Verbs, Nouns, etc… In this article, we will review the best English Grammer Topics and compare them against each other.

Adjective Clause Exercise for Class 6 CBSE Examples With Answers Pdf

Fundamentals:
An adjective clause modifies a noun or pronoun. It often uses these relative pronouns: who, whose, whom, which, and that. It sometimes uses when or where. Occasionally, the relative pronoun is understood or implied instead of directly used. Example:- Nancy made a mistake, which could be corrected.

Presentation
Read the picture story.

Adjective Clause Practice Exercise for Class 6 CBSE

A. Answer the following questions as per the story.
1. Why did Sumit take speech therapy sessions?
2. Why did Sumit start reading books?
3. What is the moral of the story?

B. Change the following sentences into adjective clause.

1. The letter brought badly needed money.
____________________________________
2. I met a girl with blue eyes.
____________________________________
3. He told us his arrival time.
____________________________________
4. We admire courageous men.
____________________________________
5. I have a box filled with almonds.
____________________________________

A. Underline the adjective clause.

1. Is that the plant that you brought?
2. How is your friend for whom I made this cake?
3. This is the house where I grew up.
4. I love to camp when it’s raining.
5. Tell me about the place where you are going.
6. What is that you brought?

B. Complete the following blanks with adjective clause.

1. Where do you keep the drink ___________?
2. Bunty is your friend ___________
3. Tanya likes the same books ___________
4. Priyanka can’t wait to take the elevator to the apartment ___________
5. Please arrange the blocks so. ___________
6. Careful with the glass of water so ___________
7. Imagine ___________ three feet into the air.

C. Underline the adjective clause in each sentence below.
Example:
That boy needs to complete all his chores.
That boy needs to complete all his chores.

1. Which person do you think will be able to complete the work?
2. The woman who lives next door brought us some cookies.
3. There is a wallet that I’d like to purchase.
4. Delhi City is where I wish to live.
5. That cat that you found belongs to our neighbour.
6. The man who wore the hat was guilty.
7. Sameer, whose friends were from out of town, had a great time.
8. Summer, which is my favourite season, is usually hot.
9. English, which is my favourite subject, has a lot of good stories.
10. Mumbai is the city where I was born.

D. Combine the two sentences. Use the second sentence as the adjective clause.

1. I saw the man. He closed the door.
_________________________________
2. The girl is happy. She won the race.
_________________________________
3. The student is from China. He sits next to me.
_________________________________
4. The students are from China. They sit in the front row.
_________________________________
5. We are studying sentences. They contain adjective clauses.
_________________________________
6. I am using a sentence. It contains an adjective clause.
_________________________________
7. ‘The taxi driver was friendly. He took me to the airport.
_________________________________

CBSE Notes for Class 8 Computer in Action – Introduction to Visual Basic

A programming language is a set of grammatical rules used for giving instructions to a computer. The two broad categories of programming languages are low-level languages and high-level languages.
We have already learnt about one of the high-level languages called QBASIC. In this chapter, we will learn about another high-level programming language called Visual Basic. We will use Microsoft Visual Basic 2010 Express which is a freely downloadable version of Visual Basic for students.

INTRODUCTION TO VISUAL BASIC
Visual Basic is a high-level programming language that offers a Graphical User Interface for designing and developing programs as compared to QBASIC that offers a text-only environment. Visual Basic offers an Integrated Development Environment (IDE) for writing programs. An IDE provides a common environment for designing, editing and removing errors in the programs.
Visual Basic is also referred to as an event-driven programming language. An event is the occurrence of some user-generated actions such as click and keypress. In Visual Basic, the code statements are executed in response to events. Let us learn more about Visual Basic.

STARTING VISUAL BASIC 2010 EXPRESS
To start Visual Basic, type Visual Basic in the Search box on the Taskbar and click the Microsoft Visual Basic 2010 Express option.The Start Page of Microsoft Visual Basic 2010 Express appears (Fig. 6.2). The Start Page has options to create a new project or open an existing project. A project is a collection of files that make up an application. You can create various types of applications in Visual Basic. In this chapter, we will learn to create a Windows Forms Application.
Follow these steps to create a Windows Forms Application.

Step 1: Click on the New Project in the Start Page (Fig. 6.2). The New Project dialog box appears.Step 2: Choose Windows Forms Application option (Fig. 6.3). You may specify the name of the Application in the Name box or you may choose to save it later.
Step 3: Click on the OK button. The Visual Basic IDE appears as shown in (Fig.6.4)

COMPONENTS OF THE VISUAL BASIC IDE
The following are the main components of Visual Basic IDE (Fig 6.4).

Title Bar
The Title bar displays the name of the project. By default, the first project is named as Windows Application 1.

Menu Bar
The Menu bar offers commands for working in Visual Basic environment. Apart from the standard menus such as File and Edit, menus such as Project, Format and Debug provide commands that are specific to programming.

Toolbar
The Toolbar contains buttons that provide shortcuts to various menu options such as the Start Debugging button.

Main Window
The Main window is the area where you work to create the application. You use this window to work with forms and edit code. There are tabs on top of the window for every opened file.
In Figure 6.4, the main window shows a form (Form 1) in the Designer view. At the top of the window, there are two tabs: the Start Page tab and the Form 1.vb [Design] tab.

Form Window
The Form window is the basic building block on which you place various objects for designing an application. It is through forms that a user interacts with an application.

Toolbox
Click on the Toolbox tab on the left edge of the screen to display the Toolbox. The Toolbox offers various tools, which can be placed on the forms for creating an interface. These tools are referred to as controls in Visual Basic (Fig. 6.5). Every form as well as control has its own set of properties, methods and events.

• Property: A property refers to the characteristics of an object such as colour and size. For example, the BackColor property lets you change the background colour of an object. You can change the properties either at the time of designing or during the execution of an application.Event: An event can be thought of as an occurrence of some user-generated action applied on an
• Method: A method is an action that can be performed on an object. For example, the Show method is used to display the form and Hide method is used to hide the form from displaying. You can call the methods at the time of execution of an application.
• Event: An event can be thought of as an occurrence of some user-generated action applied on an object. For example, click event is triggered when an object is clicked using a mouse.

Solution Explorer: The Solution Explorer window displays a list of various files of a project. The Solution Explorer window has the View Codeand the View Designerbuttons on the top to change to the Code or Designer view, respectively. You can switch between the two views to develop View Code applications in Visual Basic (Fig. 6.6).

1. Designer View: In this view, you can design the interface of an application by placing various controls on the form (Fig. 6.7).
   
2. Code View: This is the view that lets you type code statements inside the event handlers of the form or the other controls. Event handler is a code that gets executed when a particular event related to an object takes place. In this view, the drop-down box to the left provides a list of all controls used on the current form including the form itself (Fig. 6.8a). The drop-down box on the right displays a list of all the events related to the control selected in the left-side drop-down box (Fig. 6.8b).
   

Properties Window
The Properties window is used to display and change the properties of the form or of a control placed on the form. You can choose to display the properties category-wise or in the alphabetic order (Fig. 6.9).

PROPERTIES, METHODS AND EVENTS
As discussed earlier, the form as well as the controls have properties, methods and events associated with them. Let us discuss them.
Form
Table 6.1 lists the important form properties, events and methods.

CONTROLS
Pointer Control: The Pointer control is used to move and resize the controls on the form window.
Label Control: The Label control is used to display text on the form. You can use labels for identifying a Textbox or for displaying instructions to the user on the form. Table 6.2 lists some of the common properties and events associated with the Label control.

TextBox Control: The TextBox control is used for accepting text or numeric values from the user. Table 6.3 lists some of the common properties and events associated with the TextBox control.

Button ControlThe Button control is similar to push buttons initiating some action on the form. Table 6.4 lists some of the properties and events associated with the Button control

APPLICATION DEVELOPMENT
The basic steps involved in creating a Windows Application Form-based project are:
Step 1: Create a form.
Step 2: Place controls on the form.
There are two ways in which you can add controls on the form.

• Select the control in the Toolbox and then drag the control on to the form (Fig. 6.10).
  
• Double-click the control in the Toolbox. The control gets added in the top-left corner of the form. Drag the control to the desired location on the form. If required, resize the control by dragging its borders (Fig. 6.11).
  

Step 3: Set properties for the controls and the form.
Step 4: Add code to the appropriate event handlers of the form and the various objects.
Let us illustrate the process of application development with the help of some examples.
Example 1: To change the text and the foreground colour of the text when the mouse is moved over the surface of the label.
Step 1: Click on the New Project option on the Start Page (Fig. 6.12).
Step 2: Click on Windows Forms Application as the project type and enter a name for the project. In this example, we have used “first_project” as the project name (Fig. 6.13).

Step 3: Click on the OK button (Fig. 6.13). The Visual Basic IDE opens with one form named Form 1 (Fig. 6.15).
Step 4: Select the form and set the following properties in the Properties window (Fig. 6.14).
(a) Name: frmMessage
(b) Backcolor: Any colour of your choice
(c) Text: My First Application

Step 5: Double-click on the Label control in the Toolbox. Label 1 gets inserted in the form. Resize and drag it to an appropriate position as shown in Figure 6.15.

Step 6: Change the following properties of the Label control (Fig. 6.15).
(a) Name: IbIMessage
(b) Text: Move the mouse over of the following message
(c) BackColour: Any colour of your choice under the Palette tab
(d) Font: Font as Comic Sans MS, Font Style as Regular and Size as 14.
Step 7: Add one more label on the form. Drag the new label at a position below the first label as shown in Figure 6.16.

Step 8: Resize the second label control and change its following properties.
(a) Name: IbIChange
(b) Text: Secret to Success
(c) Backcolor: Any colour of your choice
(d) Font: Font as MS Sans Serif, Font Style as Bold, and Size as 14
Step 9:  Double-click on the IbIChange control to open the Code view. The Code view gets displayed. Make sure that the label IbIChange is selected in the first drop-down list. Select the MouseMove event from the second drop-down list as shown in Figure 6.17.

Step 10: The Mouse Move event handler for the label IbIChange gets inserted. Enter the given lines of code (Fig. 6.17) in the Mouse Move event handler for the label.
IbIChange. ForeColor = Color.Maroon
IbIChange.Text = “Hard Work and Determination”

Step 11: Click on the Save button on the toolbar.
Step 12: To run the application, use any one of the following ways.

• Click the Start Debugging buttonon the Toolbar, or
• Choose Debug ► Start Debugging.

When you run the application and you move the mouse over the surface of second label, the existing text is replaced and the new text Hard Work and Determination is displayed in maroon colour as shown in Figure 6.18.
Example 2: To accept the First Name and Last Name of a user in two TextBoxes, and display the Full Name on a label when the button is clicked.
Create a new Windows Forms Application project. Give the project an appropriate name. Set the form properties (Name, Back Color and Text) as you had done in Example 1 and perform the following steps.

Step 1: Add the Label, TextBox, and Button controls to the form as shown in Figure 6.19.
Step 2: Change the properties of the controls as given in Table 6.5.

The design of the form appears as shown in Figure 6.20.

Step 3: Double-click on the “Display Full Name” button and type the given code in the cmdDisplay_Click() event handler (Fig. 6.21).
IbIDisplayname.Text = txtFirst.Text + “ ” + txtLast.Text
The user enters the first name and the last name in the text boxes and clicks the Display Full Name button. The click event handler of the cmdDisplay button retrieves the values given in the first name and the last name textboxes by using the Text property and then concatenates (that is, joins the two strings) it. In order to include space between the first name and the last name, the first name is concatenated with space and then with the last name. The full name is then displayed in the IblDisplayname label using its Text property.
Step 4: Double-click on the Exit button and type End in the cmdExit_Click() event handler. The End keyword stops the execution of the program (Fig. 6.21).

Step 5: Run the application by pressing F5. When you click the Display Full Name button, the Full Name of the user is displayed in the label as shown in Figure 6.22. When you click the Exit button, the application stops executing.

CREATING A CALCULATOR IN VISUAL BASIC
Follow the given steps to create a calculator in Visual Basic that adds, subtracts and multiplies two numbers accepted from the user and displays the result in the third TextBox when the respective buttons are clicked.
Step 1: Design the form interface as shown in Figure 6.23.
Step 2: Change the Name property of the controls as given here.
(a) Number1 TextBox: txtNum1
(b) Number2 TextBox: txtNum2
(c) Result TextBox: txtResult
(d) Add Button: cmdAdd
(e) Subtract Button: cmdSubtract
(f) Multiply Button: cmdMul

Step 3: Double-click on the Add button and type the given code in the cmdAdd Click() event handler (Fig. 6.24). txtResult.Text = Val(txtNum1.Text) + Val(txtNum2.Text) The above code retrieves the value of the txtNum1 and txtNum2 textboxes by using the Text property and then adds it. A predefined function Val has been used to convert the values in the textboxes to numeric values for the purpose of addition; otherwise the values inside the textboxes are treated as text values and are concatenated. The addition of two numbers is then shown in the txtResult TextBox by using its Text property.
Step 4: Similarly, add the given code in the cmdSub_Click()’’event handler and cmdMul_Click() event handler.
For subtraction txtResult.Text = Val(txtNuml.Text) – Val(txtNum2.Text)
For multiplication
txtResult.Text = Val(txtNum1.Text) * Val(txtNum2.Text)

Step 5: Run the project by pressing F5. The Calculator Form appears as shown in Figure 6.25. Enter Number 1 and Number 2. Click on different buttons to view the result.

CBSE Class 9 Science Practical Skills – Relationship Between Weight of a Body and Force Required to Just Move it

Basic Building Concept
Friction is a part of our everyday life. Nearly every movement which we make, involves friction in one way or the other. Since our childhood, we have learnt to take advantage of it and analyse what may happen in the absence of it.

You can also Download Class 9 Science Notes PDF to help you to revise complete Syllabus and score more marks in your examinations.

Friction
Friction is a force that is comes into act whenever two surfaces move or try to move over each other.

• It opposes the relative motion of two bodies.
• The force of friction always acts in the opposite direction of motion.
• It depends on the way the bodies move over each other.
• It also depends on the texture of surfaces of both the bodies.
• It is independent of the area of contact.
• The liquids and gases also exert friction on the bodies moving through them.

Cause of Friction
According to old view, friction is caused due to interlocking between the irregularities, chumps, cracks, valleys, minute bumps or depressions on the two surfaces of bodies that are in contact.
Modern view of friction is that it is not a fundamental force but occurs because of electromagnetic forces between the charged particles which constitute the surfaces in contact.
Identifying the forces involved in friction:
We know that

• force acts in a certain direction whether it is a pull or push.
• gravitational force i.e., weight of the body always acts in downward direction i.e.towards centre of the earth.
• the direction of frictional force is always parallel to the surface and opposite to the direction of the intended motion of an object.
  Suppose a body of weight ‘W’ is kept on the table. The various forces, as discussed above, are as shown in figure.
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According to Newton’s third law of motion, the weight of the body (mg) is balanced by the reaction force ‘N’. If the block is pulled by a force ‘F’, it is compensated by the frictional force ‘F_f’, between the surfaces of body and table in contact. If we increase the applied force slowly, the body does not move till net force (F – F_f remains zero. This means that frictional force Ff increases with the increase in the force applied till the body is at rest.
This opposing nature of force, when one body tends to move over the surface of another, is called static friction.
Note:

1. Static friction does not exist by itself.
2. It is a self adjustment force in nature.
3. When there is no applied force, there is no static friction.

At some value of applied force, the body just starts to move. The magnitude of this force, which is just sufficient to move the body in the direction of applied force is called limiting friction. Therefore, the maximum value of static friction is the limiting friction.
Sliding friction: When a body slides over another, the friction acts between them is called as sliding friction.
Ex: When a body slides over a flat surface or a slope.
Rolling friction: When one body is actually rolling over the surface of another body, the friction acting between them is termed as rolling friction.
Rolling friction is always less than the sliding friction.
Ex: Rolling of wheel on the plane surface.

Friction is Necessary
Force of friction plays an important role in our daily life. In the absence of frictional force, we may not be able to be perform many activities. Some of them are given here:

1. Walking will not be possible without friction.
2. Brakes of the vehicles will not work without friction.
3. Without friction, assembling of furniture is not possible.
4. Without friction, one cannot be able to write on the paper or blackboard.

Friction is Evil

1. Due to opposing nature, extra energy has to be spent in overcoming friction.
2. It causes wear and tear and production of heat in the moving parts of a machine in contact. This could reduce the life of the machine.
   Thus, friction is a necessary evil.

Ways to Reduce Friction
Reduction in friction improves the efficiency of a machine. Some ways to reduce the friction are given below:

1. Polish the surfaces to make them smoother.
2. Add a lubricant oil or grease between the two surfaces in contact.
3. Replace sliding with rolling because rolling friction is much smaller than the sliding friction.
4. The streamline shape of body reduces the friction with air.

Aim
To establish relationship between weight of a rectangular wooden block lying on a horizontal table and the maximum force required to just move it using a spring balance.

Apparatus Required
Rectangular wooden block with a hook on one side, a spring balance (0-1000 g), a weight box and a fine thread and five pieces of mass (say each of 100 g).

Theory
Whenever an object is made to slide over another surface by applying force, force of friction opposes its motion. The direction of frictional force is always parallel to the surface and opposite to the intended motion of the object.
As the force applied on the object increases, force of friction also increases and compensates it. Net force on the body remains zero, and therefore body does not move.
On further increasing the applied force, the frictional force increases upto ascertain limit. Beyond this limit, body just begins to move as unbalanced force acts on it. This maximum value of force of friction, before the object just starts sliding over another, is called limiting friction.

Procedure

1. Clean the top of a horizontal table.
2. Take the spring balance. Note its least count and zero error.
3. Measure the weight of rectangular wooden block with the help of the spring balance and record it.
4. Take about 1m long thread. Tie one end of the thread to the hook of wooden block and other end to the spring balance.
5. Place the wooden block on the horizontal top of table in such a way that the spring balance could be held at another end of the horizontal plane surface.
   
6. Apply a small force on the wooden block by pulling the spring balance as shown in the figure below.
7. Gradually increase the force till the block just begins to slide on the horizontal table. Note the reading of the spring balance. It measures the force applied to the mass of wooden block.
8. Now keep additional weight (say 100 g) on the wooden block and repeat steps 6 and 7.
9. Repeat steps 6, 7 and 8 four more times by increasing the weight 100 g every time.
10. Record the observations in tabular form given below.

Observations
Least count of spring balance = ………… gwt.
Zero error in spring balance = …………. gwt.
Weight of the wooden block, Wb = ………… gwt.

S.No.	Weight placed on the wooden block (W) (gwt)	Total weight being pulled (Wb + W) = Normal reaction (N) (gwt)	Total force pulling the block = Reading of spring balance (Ff) (gwt)	\(\frac { { F }_{ f } }{ N }\)
1.	0
2.	100
3.	200
4.	300
5.	400
6.	500

Calculations

1. The reading of spring balance gives the maximum value of force of friction acting between the two solid surfaces just before the object sets into motion.
2. Find the ratio of total force applied to pull the block (F_f) to the total weight being pulled (N).
3. Plot a graph between total weight being pulled i.e. normal reaction along X-axis and spring balance reading i.e. limiting friction along Y-axis. The graph becomes a straight line as shown in the figure.
   

Result
It is observed that as the total weight of wooden rectangular block increases, the maximum value of force of friction also increases in the same ratio.
Thus, the graph as well as constant ratio of F_f and N indicates that the maximum force required to just move the block is directly proportional to the weight of block. This is the required relationship.
Note: Student must also perform the same experiment by taking the different nature of surfaces in contact.
i.e., extra smooth surfaces or rough surfaces. By doing so, they can observe that if there is any change in nature of surface in contact occurs, the value of limiting friction also changes accordingly.

Precautions

1. The string should be inextensible.
2. The portion of the string between the wooden block and a spring balance must be horizontal while force is applied on the block.
3. The surfaces of table and wooden block in contact must be clean and dry.
4. The mass of the rectangular wooden block should not be so large that a large force is required to make the wooden block slide.
5. Reading of the spring balance should be noted only when wooden block just begins to start.
6. Before use, adjust the zero of the spring balance.

Interactive Session

Question 1.
Why are the bodies of automobiles, aeroplanes and space launch vehicles designed in streamline shape?
Answer:
They are designed specially in streamline shape to minimise the effect of friction of air.

Question 2.
Why we say friction is a self adjusting force?
Answer:
When no force is applied on the object, friction is zero. As the applied force increases, friction also increases i.e. force of static friction is always equal to the applied force till the block starts moving. Thus, static friction adjust itself in the opposite direction of the applied force.

Question 3.
Is the maximum force required to just move the block also a self adjusting force?
Answer:
No.

Question 4.
Why is more force required to move a heavier body than to move a lighter body?
Answer:
For a heavy body, normal reaction force ‘N’ also increases. Therefore, force of friction increases. Hence, applied force also increases.

Question 5.
What are the factors on which the maximum force required to just move over the surface of a body another surface in contact depends?
Answer:
It depends on the nature of material of the surfaces in contact and their roughness or smoothness.

Question 6.
Why should the mass of rectangular block not be so large?
Answer:
It is so because the large force is required to make the wooden block slide.

Question 7.
What does happen if the block is too light?
Answer:
Observation cannot be taken as force of limiting friction may be even less than the applied force. Weight of block should be such that the spring balance shows a larger value of force just before the wooden block begins to slide.

NCERT Lab Manual Questions

Question 1.
In which direction the force of friction acts on the block?
Answer:
The force of friction acts in a direction opposite to the direction of motion of the block i.e. applied force.

Question 2.
Why is the thread used to move the block kept horizontal to the surface and the wooden block you are using?
Answer:
Applied force on the block should act in the horizontal direction.

Question 3.
How is the limiting friction between two surfaces in contact affected when grease or oil is inserted between them?
Answer:
Grease or oil fill up the irregularities of the surfaces, making them smoother. Hence limiting friction decreases.

Question 4.
How can you use the concept of limiting friction to measure force?
Answer:
The force of friction can increase only upto a certain limit. Beyond this limit, the unbalanced force acts on the body and it begins to move. Therefore, the maximum value of force of friction acting between two solid surfaces just before the object sets into motion is equal to the applied force. Thus, limiting frictional force is used to measure the applied force.

Practical Based Questions

Multiple Choice Questions/VSA (1 Mark)

Question 1.
In an experiment to establish the relationship between weight of a rectangular wooden block lying on a horizontal table and the minimum force required to just move it using a spring balance, which type of string should be used?
(a) Very high elastic
(b) Less elastic
(c) Moderate elastic
(d) Anyone can be used.

Question 2.
The portion of the string that lies between the wooden block and spring balance should
(a) make an angle of 30° with the surface of table.
(b) make an angle of 60° with the surface of table.
(c) remain horizontal and parallel to the surface in contact.
(d) remain in vertical position with the surface of table.

Question 3.
Which of the following statements about friction is true?
(а) Friction can be reduced to zero.
(b) Frictional force is directly proportional to the surface area of contact.
(c) Sliding friction is always greater than rolling friction.
(d) Frictional force can accelerate a body.

Question 4.
The value of minimum force applied on the block to just begin to move depends on
(a) nature of the two surface in contact.
(b) their state of roughness.
(c) normal reaction between the two surfaces
(d) All of the above.

Question 5.
The spring balance used for measuring minimum force required to just slide a wooden block has least count of 1 gwt. The number of divisions between its 50 gwt and 60 gwt mark should be [CBSE 2012]
(a) 50
(b) 60
(c) 20
(d) 10

Question 6.
When a body actually begins to move over the surface of another, the force of
(а) static friction comes into play.
(b) kinetic friction comes into play.
(c) limiting friction comes into play.
(d) static friction is doubled.

Question 7.
The coefficient of limiting friction between two surfaces in contact
(a) has a unit newton/metre.
(b) remains same even when two surfaces are polished.
(c) has no unit.
(d) None of the above

Question 8.
The frictional force
(a) is independent of normal reaction .
(b) opposes the relative motion between two objects.
(c) acts in the direction of applied force.
(d) is independent of nature of surfaces in contact.

Question 9.
A person can easily skate on ice but finds it difficult to move on concrete because the coefficient of friction is
(a) more on ice than concrete.
(b) more on concrete than ice.
(c) same in both.
(d) independent of normal reaction.

Question 10.
Moving objects such as an aeroplane is given streamlined shape to
I. reduce frictional force of air.
II. increase frictional force of air.
III. decrease the efficiency of the moving object.
IV. increase the efficiency of the moving object.
(a) Both I & IV are correct.
(b) Both II & III are correct.
(c) Both III & IV are correct.
(d) Both I & III are correct.

Question 11.
In an experiment, to find the relationship between the minimum force applied on the wooden block to just begin to move over another surface with the weight of body, a girl draws the forces acting on the block in four ways when it remains at rest which are


Identify which of them is correct ?
(a) I
(b) II
(c) III
(d) IV

Question 12.
In the given experiment, a student just noted down the minimum force exerted on the wooden block to just move it. He then increased the speed of sliding of wooden block on a horizontal surface, the reading of spring balance observed by him now is
(a) increases as the speed of block increases.
(b) decreases upto a certain limit as the wooden block is moved with increasing speed.
(c) remains the same as it is independent of the speed of wooden block.
(d) decreases continuously to zero as the speed of block increases.

Question 13.
In the given experiment, a student measured the minimum force required to just move a rectangular wooden block lying on a horizontal table with its largest surface using spring balance. He observed it is as F₁. He repeated the experiment with smaller surface area of the same rectangular block and find the force as F₂ now. He tried to establish a relationship between these two forces by repeating the experiment with rectangular wooden block of different dimensions. Which of the following relation would be obtained by him?
(a) F₁ = F₂
(b) F₁ > F₂
(c) F₁ < F₂
(d) There is no relation between F₁ and F₂.

Question 14.
On the basis of observations made while estab-lishing the relationship between weight of a rectangular wooden block lying on a horizontal table and the minimum force required to just move it using a spring balance, the student should find
(a) applied force is directly proportional to the weight of block.
(b) applied force is inversely proportional to the , weight of block.
(c) applied focee is equal to the weight of block.
(d) no definite relationship between them.

Question 15.
In an experiment to establish the relationship between weight of a wooden cuboid lying on the horizontal surface and the minimum force required to move it. Which of the following faces of cuboid should be in contact with the surface to exert the minimum force among the three faces of cuboid to move it?

(a) Face A with area 30 x 20 m²
(b) Face B with area 20 x 10 m²
(c) Face C with area 30 x 10 m²
(d) Any of the face A, B or C

Question 16.
While studying the relationship between weight of rectangular wooden block lying on the horizontal surface and minimum force required to just move it, Bharat applied a force on the wooden block using a spring balance. He observed that the minimum force required to just move it is 50 gwt. The magnitude of force of friction between block and table could be
(a) 50 gwt
(b) – 50 gwt
(c) 0
(d) greater than 50 gwt

Question 17.
Lubricants such as grease or oil
(a) reduce the force of friction
(b) increase the force of friction
(c) have no role in friction.
(d) neither increase nor decrease friction.

Question 18.
In an experiment, a student took two wooden blocks having the same mass but different dimensions. He observed that the minimum force read by the spring balance to just move the block would remain the same. He concluded that
(a) force of limiting friction depends on the area of the surfaces in contact.
(b) force of limiting friction is independent on the area of the surfaces in contact.
(c) force of limiting friction does not depend on the normal reaction.
(d) force depends on dimensions of the body.

Answers

1. (b)
2. (c)
3. (c)
4. (d)
5. (d)
6. (b)
7. (c)
8. (b)
9. (b)
10. (a)
11. (b)
12. (b)
13. (a)
14. (a)
15. (b)
16. (b)
17. (a)
18. (b)

Short Answer Questions (2 Marks)

Question 1.
A force applied on a block with constant mass increases gradually by pulling the spring balance. Will the force of friction increase until a point?
Answer:
Yes, it would increase till the limiting friction is experienced by the block. Further increase would lead to the block accelerating to the direction in which the force is being applied.

Question 2.
What is limiting friction?
Answer:
Limiting friction is the maximum value of the opposing force which comes into play when one body is just at the verge of moving over the surface of another body.

Question 3.
On the observation made while establishing the relationship between weight of a rectangular wooden block lying on a horizontal plane and minimum force required to just move it using a spring balance, a student plot the given graph between the force of limiting friction ‘F’ and normal reaction ‘N’ (equal to weight of the block) for the two different blocks ‘A’ and ‘B’ of the same material. Which of them has smooth surface in contact with the plane?

Answer:
The magnitude of force of limiting friction ‘F’ is directly proportional to the weight of the block, i.e. normal reaction ‘N’,
i.e. F ∝ N
or F = µN
where µ = F/N
= Constant of proportionality
= Slope of F-N curve
The given graph indicates that slope for block ‘B’ is greater. Therefore, for block ‘A’ force of friction is smaller and for block ‘B’, it is larger. Hence, the surface of block ‘A’ in contact with the plane must be smoother.

Question 4.
Why is the less elastic thread used to move the block kept horizontal to the surface in the experiment to establish the relationship between weight of a rectangular wooden block you are using and minimum force required to just move it using a spring balance?
Answer:
The string should be inextensible, i.e. unable to be stretched or drawn out in length so that total applied force must be exerted only on the block.

Question 5.
Does the force of friction vary with

1. weight of the block?
2. change in the conditions of surface in contact?
3. area of contact?

Answer:

1. Yes, it is directly proportional to the weight of the block under consideration.
2. Yes
3. No

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Looking for an easy way to Learning of new elementary english grammar and composition for class 7 answers, Solutions. You have to learn basic English Grammar topics like Tenses Verbs, Nouns, etc… In this article, we will review the best English Grammer Topics and compare them against each other.

Demonstrative Exercises for Class 7 CBSE Examples Pdf

Demonstratives are words that show which person or thing is being referred to, in a sentence:
For Examples:

• This is my brother’.
• ‘This’ is a demonstrative.

The demonstratives in English are this, that, these, and those. Demonstrative pronouns vs demonstrative adjectives. A distinction must be made between demonstrative adjectives (or demonstrative determiners) and demonstrative pronouns (or independent demonstratives).

A demonstrative adjective modifies a noun.
This apple is good. I like those houses. (This modifies ‘apple’ and those modifies ‘houses’). A demonstrative pronoun stands on its own, replacing rather than modifying a noun. This is good. I like those. (This and those don’t modify any nouns they stand alone and replace other nouns.)

Use of demonstratives:

• Demonstratives differ according to :distance: near or far, or number: singular or plural. Here are the main distinctions:
• This modifies or refers to singular nouns that are near the speaker.
• That modifies or refers to singular nouns that are far from the speaker.
• These modifies or refers to plural nouns that are near the speaker.
• Those modifies or refers to plural nouns that are far from the speaker.

Presentation:
Read the picture story.
A. Answer the following questions.
1. Which students are declared as final contestants?
2. What are the criteria of selection of contestants?
3. How is the declamation contest beneficial for the narrator of the story?

B. Fill in the blanks below with this, that, these and those.

Near: __________ (Singular) __________ (Plural)
Far: __________ (Singular) __________ (Plural)

Demonstrative Exercises With Answers for Class 7

A. Help Pooja to describe her office. Write this or these for things that are near her, and that or those for things that are not near her. The first one has been done for you.

1. This phone is new.
2.__________ closet is for her coats.
3.__________ books are about business.
4 __________ computer is old.
5.__________ pens are very good.
6.__________ window is open.
7.__________ papers are for the meeting.
8. __________ cabinet is for paper clips, folders, and general office things.
9. __________ picture is a photograph of her family.
10. __________ folders are for the sales reports.

B. Underline the demonstrative pronouns and demonstrative adjectives. Write ‘D’ for the demonstrative pronoun and ‘A’ for the demonstrative adjectives. The first one has been done for you.

1 A Those cattle are running away.
2. __________ This is the last straw.
3. __________ I gave you those books yesterday.
4. __________ I will forget this if I don’t write it down.
5. __________ These actors are very skilled.
6. __________ I can readily see that.
7. __________ This fruit is rotten.
8. __________ Give me that hat.
9. __________ That is all there is.
10. __________ Those are stinky.

C. Rewrite the sentences in ‘plural form’. The first one has been done for you.

1. That is a dictionary. Those are dictionaries.
2. That is a baby. __________
3. ‘This is a present __________
4. This is an umbrella __________
5. That isn’t a hamster. __________
6. Is that a newspaper? __________
7. Is this a postcard? __________
8. Is that a Spanish flag? __________
9. Is this a fly? __________
10. Is this a sheep? __________

D. Put the words in the correct order. The first one has been done for you.

1. over there/box/is/that/a Is that a box over there?
2. what/pillows/are/colour/these __________?
3. this/her/is/play station/new __________
4. difficult/are/exercises/these __________
5. that/whose/is/village __________?
6. knives/those/look/at __________
7. daughters/my/are/these __________
8. guests/are/in/garden/those/the/our __________
9. this/model’s/is/ favourite/your/poster __________
10. eyeglasses/are/my/these/father’s __________

E. Fill in the blanks with ‘this’, ‘that’, ‘these’, or ‘those’.

Ex: “This is a bus and these are cars”.

1. __________ a wolf and __________ wolves, (far)
2. __________ some oil and __________ some sugar cubes, (near)
3. __________ a mouse and __________ mice, (near)
4.__________ a fish and __________ fish, (near)
5. __________ a toy and __________ some toys, (far)

F. Write the questions to these Answer:s.

Ex:

• A: “What is this?”
• B: “It’s a subway.”

1. __________ ? (that)
It’s a butterfly.
2. __________ ? (those)
They’re keys.
3. __________? (these)
They’re policemen.
4. __________ ? (this)
It’s a ticket.
5. __________ ? (those)
They’re radios.

CBSE Class 10 Science Practical Skills – Resistors in Parallel

BASIC BUILDING CONCEPTS

Parallel combination of resistors
The arrangement of resistors in which they are connected in such a way that their one end will be at higher potential and other end at lower potential is called parallel combination.

Characteristics of parallel combination

1.  Voltage across each resistor is same and is equal to the applied voltage.
2.  Current through each resistor is inversely proportional to the resistance of that resistor, i.e.
   I α1/R
3. Total current flowing in the circuit is the sum of the individual currents flowing in the different branches, i.e.,
   I=I1+I2+I3
4.  The reciprocal of the equivalent resistance is equal to the sum of the reciprocals of the individual resistance, i.e.
   1/Rp=1/R1+1/R2+1/R3
5. The equivalent resistance is smaller than the least resistance used in the circuit, i.e.
   Rp<R1, Rp<R2, Rp<R3……, etc
   Therefore, due to the above characteristics of the parallel circuits, all the household electrical appliances are connected in a parallel combination.

Uses of parallel circuit
It is used when

1. the resistance in the circuit is to be decreased.
2.  the current in the circuit is to be increased.

Therefore, for a household purpose, all electrical appliances are connected in parallel combination so that they get the same voltage from the power supply line and thus, work properly.

You can also download NCERT Class 10 Science Solutions to help you to revise complete syllabus and score more marks in your examinations.

AIM
To determine the equivalent resistance of two resistors when connected in parallel.

MATERIALS REQUIRED
Two standard resistance coils, ammeter, voltmeter, one-way plug key, a low resistance rheostat, connecting wires, battery or battery eliminator.

THEORY
Parallel combination of resistors: An arrangement in which a number of resistors are connected between two common points in such a way that the potential difference across each resistor is equal to the applied voltage is called parallel combination of resistors.
If Rp is the equivalent resistance of the given parallel combination having the same potential difference as the applied potential, then  1/Rp=1/R1+1/R2  or  Rp=R1R2/R1+R2

Circuit Diagram

Assembly Diagram
Connect all the resistors in parallel combination between the two terminals of the voltmeter as shown in the figure given below.

PROCEDURE

1.  Connect the circuit in the similar manner as shown in circuit diagram or apparatus arrangement with one of the unknown resistors.
2.  Find the values of two given unknown resistors R1 and R2 by adopting the procedure given in experiment 5 and record the observations in the observation table.
3. Using Ohm’s law, find the value of each resistance. Let it be R1 or Rr
4. Connect the given resistors in parallel combination between the two terminals of the voltmeter as shown in figure above.
5.  Put the plug in the key and take the readings of ammeter and voltmeter.
6.  Repeat step 5 three times by changing the position of the sliding contact of the rheostat.
7. equivalent resistance of the combination.

OBSERVATION TABLE

OBSERVATIONS
1. Least count of ammeter = ……..A
2. Zero error of ammeter = ……..A
3. Least count of voltmeter = ……..V
4. Zero error of voltmeter = ……..V
5. Zero correction of ammeter = ……..A
6. Zero correction of voltmeter = ……..V

CALCULATIONS

1.  Mean value of Ry =……….. Ω
2.  Mean value of R2 =……….. Ω

Equivalent value of parallel combination:

1.  by calculation, Rp’ = R1R2/R1+R2 = ………… Ω
2.  by experiment, Rp =R1R2/R1+R2  =  ………… Ω

RESULT :

1.  The equivalent resistance of parallel combination = ………… Ω
2.  There is a close agreement between the calculated value and the experimental value.
   Hence,1/Rp=1/R1+1/R2 is verified

PERCENTAGE ERROR
Percentage error = Experimental value – Calculated value /Calculated value = Rp-R’p/R’p ×100

SOURCE OF ERROR

1. Reading error may be possible while observing the pointer of ammeter and voltmeter.
2. Thick connecting wires may not be available at the time of performing the experiment.
3. Area of cross-section of resistor may not be uniform across the length of wire.
4. There may be the use of high resistance rheostat.
5.  Current may be allowed for a longer period of time.
6.  The terminal screws of the instrument may not be tightened properly.

INTERACTIVE SESSION

Question 1:
Which physical quantity remains the same in parallel combination: current or voltage?
Answer:
Voltage

Question 2:
Why does the total resistance decrease in a parallel combination?
Answer:
In a parallel combination, the resultant cross-sectional area of conductor increases. Hence, the total resistance decreases.

Question 3:
How does the resistance depend upon the area of cross-section of the conductor?
Answer:
It is inversely proportional to the area of cross-section of the wire, i.e. Rα 1/A

Question 4:
Can you distinguish between resistor and resistance?
Answer:
A resistor is a device that offers resistance, whereas resistance, is the property of the resistor.

Question 5:
What is the direction of current sent by a cell?
Answer:
The direction of current sent by a cell in the circuit is from positive terminal to negative terminal outside the cell.

Question 6:
How many times will the equivalent resistance of two identical resistors be increased if the parallel arrangement is changed to series arrangement?
Answer:
The effective resistance of parallel combination is Rp = R/2and that of series is Rs = 2R
Therefore Rs = 4Rp , i.e. equivalent resistance increases four times.

Question 7:
Why is a voltmeter connected in parallel across the conductor?
Answer:
To measure the maximum potential difference developed across the ends of a conductor, a high resistance device voltmeter is connected in parallel.

Question 8:
In what ratio the current divides itself in the parallel combination?
Answer:
The current divides itself into the inverse ratio of the resistance, i.e. I α 1/R

Question 9:
Suppose in a combination, we find that the equivalent resistance is smaller than the smallest resistance used in the circuit. Which type of combination is present in the circuit?
Answer:
It is a parallel combination.

Question 10:
Why is an ammeter connected in series in a circuit?
Answer:
To measure the amount of electric current flowing in a circuit, ammeter is always connected in series with the circuit as it is a low resistance device.

Question 11:
What do you mean by the range of ammeter?
Answer:
It is the maximum value of current which the ammeter can measure.

NCERT LAB MANUAL QUESTIONS

Question 1:
Two resistors having resistances of 4 Ω and 6 Ω respectively are connected in a circuit. It was found that the total resistance in the circuit is less than 4 Ω. In what way the resistances would have been connected?
Answer:
According to the given condition, resistors of 4Ω and 6Ωare connected in parallel combination.
In parallel combination,
1/Rp=1/R1+1/R2 =1/4 +1/6=5/12
Therefore R = 2.4 Q

Question 2:
Two resistors are connected first in series and then in parallel. What effect will it have on the readings of voltmeter and ammeter?
Answer:
There will be no change in the reading of voltmeter because applied voltage remains the same in both the cases but ammeter reading will be less in case of series combination as compared to parallel combination
of the same resistors because Rs > Rp and  I α 1/R(for constant applied voltage) as shown in the following
circuit diagrams.

Question 3:
In what way household appliances should be connected?
Answer:
The household appliances should be connected in parallel in order to get equal voltage for each appliance and ensure that if one switch is ‘on’ or ‘off, others are not affected.

PRACTICAL BASED QUESTIONS
Multiple Choice Questions/VSA

Question 1:
For three circuits shown here,

the same two resistors R3 and R2 have been connected in parallel in all the circuits but the voltmeter and the ammeter have been connected in three different positions. The relation between the three voltmeter and ammeter readings would be [CBSE 2012, Delhi 2009]
(а) V1 = V2 = V3 and I1 = I2 = I3
(б) V1 ≠ V2≠ y3 and I1 = I2 = I3
(c) V1 = V2 = V3 and 11≠ I2 ≠I/3
(d) V1 ≠V2 ≠V3 and  I1≠ I2≠ I3

Question 2:
Two students setup their circuits for finding the equivalent resistance of two resistors connected in parallel in two different ways as shown.

The circuit(s) likely to be labelled as correct
(a) are neither of the two circuits
(b) is only circuit I
(c) is only circuit II
(d) are both the circuits

Question 3:
In the experiment on finding the equivalent resistance of two resistors, connected in parallel, two students connected the ammeter in two different ways as shown in given circuits I and II. The ammeter has been correctly connected in

(a) circuit (I) only.
(b) circuit (II) only.
(c) both the circuits (I) and (II).
(d) neither of the two circuits.

Question 4:
 A student did the experiment to find the equivalent resistance, of two given resistors, R] and R.v first when they are connected in series and next when they are connected in parallel. The two values of the equivalent resistance obtained by him were Rs and R respectively. He would find that
(a) Rs > Rs
(b) Rp > Rs
(c) Rs = Rp=(R1+R2/2)
(d) Rs = Rp but not equal to (R1+R2/2)

Question 5:
The voltmeter, ammeter and resistance in the circuit shown have been checked to be correct. On plugging the key, the ammeter reads 0.9 A, but the voltmeter reads zero. This could be because

(a) the range of the voltmeter is more than twice the battery voltage.
(b) the least count of the voltmeter is too high.
(c) the wires joined to the voltmeter terminals are loose.
(d) the voltmeter is incorrectly placed in the circuit.

Question 6:
On plugging the key, the voltmeter/ammeter is likely to be damaged in the circuit shown in figure

(a) A
(b) B
(c) C
(d) D

Question 7:
To determine the equivalent resistance of two resistors in parallel combination, a circuit is shown below. The component of the circuit whose terminals are wrongly connected is

(a) rheostat
(b) cell
(c) voltmeter
(d) ammeter

Question 8:
In the experiment on finding the equivalent resistance of two resistors, connected in parallel, three students connected the voltmeter in their circuits, in the three ways, X, Y and Z as shown here.

The voltmeter has been correctly connected in
(a) cases X and Y only
(b) cases Y and Z only
(c) cases Z and X only
(d) all the three cases.

Question 9:
To determine the equivalent resistance of three resistors arranged in parallel, four students connected the resistors as shown in figures A, B,
C and D.

The correct set-up is that of student
(a) A
(b) B
(c) C
(d) D

Question 10:
The voltmeter, ammeter and resistance in the circuit shown have been checked and found to be correct. On plugging the key, the voltmeter reads 4.5 V, but the ammeter reads 1.5 A.

This could most likely be because the wires joined to
(а) the resistor R1 is loose.
(б) the resistor R2 is loose.
(c) both the resistors R1 and R2 are loose.
(d) the ammeter terminals are loose.

Question 11:
Out of the four circuits shown for studying the equivalent resistance of two resistor/resistors when connected in parallel, the correct sequence of procedure is


(a) (i), (ii), (iv) and (iii)
(b) (i), (iii) and (ii) only
(c) (iii), (i) and (ii) only
(d) (iv), (ii), (i) and (iii)

Question 12:
A student uses a battery of adjustable voltage 0-6 V. She has to perform an experiment to determine the equivalent resistance of two resistors when connected in parallel using two resistors of value 3 Ω and 6 Ω. The best choice of combination of voltmeter and ammeter to be used in the experiment is
(a) ammeter of range 0 – 5 A and voltmeter of range 0-10 V
(b) ammeter of range 0 – 5 A and voltmeter of range 0-5 V
(c) ammeter of range 0 – 2 A and voltmeter of range 0-10 V
(d) ammeter of range 0 – 5 A and voltmeter of range 0-2 V

Question 13:
You have two resistors R terminals marked a, b, c and d as shown.

In order to find the equivalent resistance of parallel combination of the two resistors f?1 and R2 how would you connect the terminals of the resistors Rr and R2 to the terminals X and Y in the circuit shown in the figure.
(a) X to a ; b to c and d to Y
(b) a and b both to X ; c and d both to Y
(c) a and c both to X ; b and d both to Y
(d) X to d ; c to b and a to Y

Question 14:
In the circuit shown below, the voltmeter and ammeter reading would be

(a) 3 V and 0.5 A
(b) IV and 3 A
(c) 3 V and 1A
(d) 3 V and 3 A

Question 15:
If a student while performing the experiment for finding the equivalent resistance of two resistors when connected in parallel keeps the circuit closed for a long time to measure the current and potential difference, then
(a) ammeter’s zero point will change.
(b) ammeter will show higher reading than the actual one.
(c) voltmeter will show higher reading than actual one.
(d) resistor will get heated up and its value will change.

Question 16:
The current ratio I1/I2 depends upon

(a)R1 and V
(b)R2 and V
(c)R1,R2 and V
(d)R1 and R2 only

Short Answer Questions

Question 1:
Draw a circuit diagram to show three resistors connected in parallel with a cell and a key. Write formula for the equivalent resistance R of this combination if the individual resistances of the resistors are Rx, R2 and R3.

Question 2:
Study the following circuit and answer the questions that follow:

(a) State the type of combination of the two resistors in the circuit.
(b) What will be the potential difference across the above combination if applied potential in 6 V?

Question 3:
In the circuit diagram given below, calculate:

(a) the total effective resistance of the circuit.
(b) the total current in the circuit.

Question 4:
List in a tabular form, two differences between a voltmeter and an ammeter.

Question 5:
To determine the equivalent resistance of two resistors Rj and R2 when connected in parallel, a student chooses the resistors to perform the experiment in such a way that Rx > R2. After taking observations, he plots the V-I graph for the same. Draw the same V-I graph as he plotted by taking ‘V’ on Y-axis and T on X-axis for
(i) R1 and R2, and
(ii) R1 and R2, and their equivalent resistance on
the same axis.
Give justification for both the cases.

ANSWER KEY
Multiple Choice Questions/VSA

1. (c)
2. (b)
3. (a)
4. (a)
5. (c)
6. (c)
7. (d)
8. (d)
9. (6)
10. (b)
11. (c)
12. (a)
13. (c)
14. (c)
15. (d)
16. (d)

Short Answer Questions

1.

2. (a) The circuit shows the parallel combination of the two resistors.
(b) The potential difference across the combination is 6 V because their one end is connected at higher potential and other end is at lower potential of the 6 V battery.

3.

4.

5. (i) The slope of V-I graph gives the resistance of the resistor used in the experiment. As Rj > R2, the slope for R, must be greater then the slope for R2.

(ii) In the parallel combination, the equivalent resistance is less than the least value resistance in the circuit. So in the V-I graph slope for parallel combination is less than that of R2.

Science Practical SkillsScience LabsMath LabsMath Labs with Activity

CBSE Class 9 Science Practical Skills – Types of Reactions and Changes

EXPERIMENT

AIM
To carry out the following reactions and classify them as physical or chemical changes.

1. Iron with copper sulphate solution in water
2. Burning of magnesium in air
3. Zinc with dilute sulphuric acid
4. Heating of copper sulphate
5. Sodium sulphate with barium chloride in the form of their solutions in water.

 

(1) Reaction between Iron and Copper Sulphate solution in water

MATERIALS REQUIRED
Two iron nails, CuS0₄ solution, test tube, clamp stand, thread.

THEORY
Pure iron is greyish in colour. Pure copper is reddish brown in colour. Due to the presence of Cu²⁺ ions, aqueous C solution of copper sulphate is blue. Due to the presence of Fe²⁺ ions, aqueous solution of ferrous sulphate is pale green. Iron being more reactive than copper displaces copper from its salt solution.

PROCEDURE

1. Clean an iron nail by rubbing with sand paper so that it appears greyish.
2. Take two test tubes and labelled them as A and B. In both test tubes, add 10 ml of freshly prepared copper sulphate solution and fix these test tubes in two separate clamp stands (Fig 4.1).
3. Tie a thread to the nail and hang it in test tube B. Care should be taken so that the iron nail is completely immersed in CuS0₄ solution. Tie other end of thread to stand as shown in Fig 4.1.
4. Keep the other iron nail on a white sheet of paper.
5. Leave the set-up undisturbed for sometime.
6. Remove the nail from the solution and keep it along the side of second iron nail on sheet of paper. Record your observations.

OBSERVATION AND INFERENCE

RESULT
The reaction between Fe and CuS0₄ shows that Fe is more reactive than Cu and the reaction is a displacement reaction.

PRECAUTIONS

1. Clean the iron nail properly by rubbing with sand paper.
2. Copper sulphate solution is poisonous, so, handle it with care.
3. During experiment, the test tubes should not be touched or disturbed.
4. After completing experiment, iron nail coated with copper should not be touched.

(2) Burning of Magnesium in air

MATERIALS REQUIRED
Magnesium Ribbon, burner, tongs, watch glass, pH paper strip/red litmus paper.

THEORY
Magnesium is a very active metal. It reacts with oxygen to form magnesium oxide.

During this process two elements viz, magnesium and oxygen combine together to form a single compound magnesium oxide. Such type of reactions are called combination reactions.
Magnesium oxide is basic in nature because when this is dissolved in water it forms magnesium hydroxide which is basic in nature.

Magnesium oxide turns red litmus solution blue.

PROCEDURE, OBSERVATION AND INTERFENCE

RESULT
Mg burns in air giving out a flash of bright white light and combines with oxygen to form basic magnesium oxide. MgO is basic in nature

PRECAUTIONS

1. Magnesium ribbon should be cleaned by rubbing with sand paper.
2. Hold magnesium ribbon using tongs while burning it.
3. Do not look at the bright light associated with burning Mg directly. Use sun glasses.
4. White powder or magnesium oxide should not be touched.

(3) Reaction of Zn with dil. Sulphuric Acid

MATERIALS REQUIRED
Zinc granules, dil. H₂S0₄ , clamp stand, boiling tube, cork fixed with a fine capillary tube.

THEORY
Zinc being more reactive or lying above hydrogen in the reactivity series, displaces hydrogen from dil. acids.

Zn(s) + H₂S0₄ (aq) → ZnS0₄ (aq) +H₂(g)

PROCEDURE,OBSERVATION AND INFERENCE

RESULT
Zinc reacts with sulphuric acid to produce hydrogen gas and zinc sulphate.
Zn(s) + H₂S0₄ (aq) → ZnS0₄ (aq) +H₂(g)

PRECAUTIONS

1. Handle the chemicals with care.
2. Use a small jet to test hydrogen gas, as hydrogen gas burns instantaneously with an explosion.

(4) Heating of Copper Sulphate

MATERIALS REQUIRED
Hydrated copper sulphate, test tube, test tube holder, burner, pH paper or blue litmus paper.

THEORY
Chemical formula of copper sulphate pentahydrate is CuS0₄.5H₂0 . It contains five moles of water per mole of copper sulphate. Because of water of hydration, the colour of copper sulphate pentahydrate is blue. When it is heated, it loses water molecules and turns to white coloured anhydrous copper sulphate.

The above process can be reversed. When water is added to anhydrous copper sulphate, its colour changes to blue. This shows that coloured hydrated copper sulphate has regained.

On further heating, anydrous copper sulphate decomposes to form sulphur trioxide gas and copper oxide.

The whole change of heating of copper sulphate pentahydrate can be given by the following equation:

The reaction in which a substance breaks down to form more than one products is called decomposition reaction.

PROCEDURE,OBSERVATION AND INFERENCE

RESULT 
The hydrated copper sulphate loses water of crystallisation on gentle heating and becomes dirty white. On further heating strongly, it decomposes to black copper oxide and pungent smelling sulphur trioxide.

PRECAUTIONS

1. Copper sulphate is a poisonous substance. Do not touch or taste it.
2.  Sulphur trioxide coming in contact with atmospheric moisture forms sulphuric acid. So, contact with sulphur trioxide must be avoided.
3. In the beginning of experiment, copper sulphate should be heated gently. But after the formation of anhydrous copper sulphate test tube should be heated strongly.

(5) Reaction between Sodium Sulphate and Barium Chloride in the form of their Aqueous Solutions

MATERIALS REQUIRED
Test tube, test tube holders, aqueous solution of sodium sulphate and barium chloride.

THEORY

On mixing the solutions of sodium sulphate and barium chloride, a white precipitate of barium sulphate is formed which in insoluble in water. This chemical change can be represented by the following chemical equation:

In this reaction, white precipitate of BaS04 is formed by the reaction ofS0₄^2-and Ba²⁺. The other product formed is sodium chloride which remains in the solution. Such reactions in which there is an exchange of ions between the reactants are called double displacement reactions.

 

PROCEDURE, OBSERVATION AND INFERENCE

RESULT
The reaction between Na₂S0₄ (aq) and BaCl₂ (aq) yields an insoluble white precipitate of BaS0₄, indicating that the reaction is a double displacement reaction.

PRECAUTIONS

1. Use the chemicals in small amounts.
2. Wash your hands with soap after completing the experiment.

 

INTERACTIVE SESSION

Examiner :
What do you understand by a chemical reaction?
Examinee:
It is a chemical change in which bonds between reactants are broken and new bonds are made leading to new substances being formed with new properties.

Examiner :
Is it possible that only a reduction or oxidation reaction occurs?
Examinee:
No, reduction and oxidation reactions always occur together.

Examiner :
Why do displacement reactions occur?
Examinee:
Displacement reactions occur due to the difference in reactivities of metals.

Examiner :
What happens in a displacement reaction?
Examinee:
A more reactive metal displaces a less reactive metal from its salt solution.

Examiner :
Why do metals have different reactivities?
Examinee:
Metals have different reactivities because their electron donating tendency is different and all metals react by donating electrons.

Examiner :
Why is hydrogen displaced from the acid solution on reaction of zinc with dil. H₂S0₄?
Examinee:
Hydrogen is displaced because Zinc is more reactive than hydrogen.

Examiner :
Give the colours of CuS0_4.5H₂0 and anhydrous CuS0₄.
Examinee:
Blue and dirty white respectively.

Examiner :
At what temperature, CuS0₄.5H₂0 loses four molecules of water?
Examinee:
100 °C

Examiner :
At what temperature, it loses five molecules of water?
Examinee:
250 °C

Examiner :
What is anhydride of H₂S0₄? Give its colour and odour.
Examinee:
S0₃. It is colourless and pungent smelling gas.

Examiner :
Which acid is formed when S0₃ is dissolved in H₂0?
Examinee:
H₂S0₄ is formed.

Examiner :
What type of reaction is heating of CuS0₄ strongly?
Examinee:
Decomposition reaction.

NCERT LAB MANUAL QUESTIONS 

Question 1:
Why should magnesium ribbon be cleaned before burning it in air?
Answer:
Magnesium ribbon should be cleaned before burning to remove the oxide layer deposited over the magnesium ribbon which makes it passive, so that it can ignite easily.

Question 2:
Why does the red litmus paper turn blue when touched with aqueous solution of magnesium oxide?
Answer:
When magnesium oxide is dissolved in water, it forms magnesium hydroxide which is basic in nature. So aqueous solution of MgO turns red litmus paper blue.

Question 3:
Is there a possibility of a compound other than MgO formed in the reaction of magnesium with air?
Answer:
Yes, Mg also reacts with N2 present in air to form magnesium nitride (Mg₃N₂).
3Mg(s) +N₂(g) → Mg₃N₂(s)

Question 4:
Why is it suggested to wear dark coloured goggles while watching the burning of magnesium ribbon in air?
Answer:
In order to prevent our eyes from the dazzling light produced.

Question 5:
Write the chemical reaction of zinc with dil. sulphuric acid.
Answer:

Question 6:
How does the combustion of hydrogen gas produce water?
Answer:

Question 7:
How will you show that the hydrogen gas is neutral in behaviour?
Answer:
Hydrogen gas neither turns red litmus paper blue nor it turns blue litmus paper red.

Question 8:
Fill in the blanks:

1. Sodium sulphate and barium chloride are………. (ionic/covalent) compounds.
2. As the white precipitate of barium sulphate is formed………… (immediately/sometime
   after mixing the two solutions), the reaction between………….. (ionic/covalent)
   compounds is………… (instantaneous/slow).

Answer:

1. ionic
2. immediately, ionic, instantaneous.

Question 9:
Why does the colour of copper sulphate solution change when an iron nail is dipped in it?
Answer:
The colour of copper sulphate solution changes from blue to pale green when an iron nail is dipped in it because Fe is more reactive than Cu and can displace it from its salt solution.

Question 10:

Answer:
The above reaction occurs because chlorine is more reactive than iodine and, therefore, displaces iodide ions from solution.

PRACTICAL BASED QUESTIONS
Multiple Choice Questions/VSA

Question 1:
Which one is true about the behaviour of MgO in the presence of water?
(a) It is basic.
(b) It is acidic.
(c) It is amphoteric,
(d) It is neutral.

Question 2:
When dilute hydrochloric acid is added to granulated zinc placed in a test tube, the observation made is
(a) the surface of the metal turns shining.
(b) the reaction mixture turns milky.
(c) greenish yellow gas is evolved.
(d) the colourless and odourless gas evolves with bubbles.

Question 3:
S0₃  is
(a) acidic
(b) basic
(c) neutral
(d) amphoteric.

Question 4:
2H₂ + 02 →2H₂0 is an example of
(a) displacement reaction
(b) decomposition reaction
(c) combination reaction
(d) isomerisation reaction

Question 5:
When a process ‘X’ is applied to anhydrous copper sulphate, it turns blue. Here the process ‘X’ represents
(a) heating at 150°C
(b) heating at 110°C
(c) dissolution in water
(d) all of these

Question 6:

Question 7:
Combustion is an example of
(a) displacement reaction
(b) redox reaction
(c) decomposition reaction
(d) isomerisation reaction.

Question 8:
We will observe a precipitate to occur in the solutions when
(a) barium chloride is added to sodium sulphate.
(b) barium chloride is added to sodium chloride.
(c) sodium sulphate is added to sodium chloride.
(d) hydrochloric acid is added to barium chloride.

Question 9:
Barium sulphate is
(a) soluble in water.
(b) partially soluble in water.
(c) insoluble in water,
(d) a gas at room temperature.

Question 10:
Iron displaces copper from its salt solution because
(a) both Fe and Cu are equally reactive
(b) Fe is less reactive than Cu
(c) Fe is more reactive than Cu
(d) none of the above.

Question 11:
Sodium sulphate and barium chloride solutions are mixed in a test tube. The observation made is:
(a) greenish yellow gas is evolved
(b) a colourless gas is evolved
(c) a yellow precipitate is formed
(d) a white precipitate is formed.

Question 12:
Iron filings were added to a solution of copper sulphate. After 10 minutes, it was observed that the blue colour of the solution changes and a layer gets deposited on iron filings. The colour of (i) the solution and (ii) that of the coating on iron filings would respectively be
(a) (i) yellow and (ii) green.
(b) (i) brown and (ii) blue.
(c) (i) red and (ii) greenish blue.
(d) (i) green and (ii) reddish brown.

Question 13:
100 ml of a saturated copper sulphate solution was taken in a beaker. A small amount of iron filings was added to the beaker and left undisturbed overnight. The mixture was then filtered to obtain the residue. The colour of the residue was found to be
(a) greenish blue
(b) faint green
(c) steel grey
(d) reddish brown.

Question 14:
Which of the following is a double displacement reaction?

Question 15:

(a) This is a single displacement reaction
(b) The produced gas ‘X’ is acidic
(c) Zn is less reactive than hydrogen
(d) All of the above.

ANSWER KEY
Multiple Choice Questions/VSA

1. (a)
2. (d)
3. (a)
4. (c)
5. (c)
6. (a)
7. (b)
8. (a)
9. (c)
10. (c)
11. (d)
12. (d)
13. (d)
14. (b)

Science Practical SkillsScience LabsMath Lab ManualMath Labs with ActivityMath Labs

CBSE Previous Year Solved  Papers  Class 12 English Delhi 2016

Time allowed : 3 hours                                                                                           Maximum Marks: 100
General Instructions :

1. This paper is divided into three sections : A, B and C. All the sections are compulsory.
2. Separate instructions are given with each section and question, wherever necessary. Read these instructions very carefully and follow them faithfully.
3. Do not exceed the prescribed word limit while answering the questions.

SET I

SECTION —A
(READING)

Question. 1. Read the passage given below:

1. Maharana Pratap ruled over Mewar only for 23 years. However, he accomplished so much grandeur during his reign that his glory surpassed the boundaries of countries and time turning him into an immortal personality. He along with his kingdom became a synonym for valour, sacrifice and patriotism. Mewar had been a leading Rajput kingdom even before Maharana Pratap occupied the throne. Kings of Mewar, with the cooperation of their nobles and subjects, had established such traditions in the kingdom, as augmented their magnificence despite the hurdles of having a smaller area under their command and less population. There did come a few thorny occasions when.the flag of the kingdom seemed sliding down. Their flag once again heaved high in the sky thanks to the gallantry and brilliance of the people of Mewar.
2. The destiny of Mewar was good in the sense that barring a few kings, most of the rulers were competent and patriotic. This glorious tradition of the kingdom almost continued for 1500 years since its establishment, right from the reign of Bappa Rawal. In fact only 60 years before Maharana Pratap, Rana Sanga drove the kingdom to the pinnacle of fame/ His reputation went beyond Rajasthan and reached Delhi. Two generations before him, Rana Kumbha had given a new stature to the kingdom through victories and developmental work. During his reign, literature and art also progressed extraordinarily. Rana himself was inclined towards writing and his works are read with reverence even today. The ambience of his kingdom was conducive to the creation of high quality work of art and literature. These accomplishments were the outcome of a longstanding tradition sustained by several generations.
3. The life of the people of Mewar must have been peaceful and prosperous during the long span of time; otherwise such extraordinary accomplishment in these fields would not have been possible. This is reflected in their art and literature as well as their loving nature. They compensate for lack of admirable physique by their firm but pleasant nature. The ambience of Mewar remains lovely thanks to the cheerful and liberal character of its people.
4. One may observe astonishing pieces of workmanship not only in the forts and palaces of Mewar but also in public utility buildings. Ruins of many structures which are still standing tall in their grandeur are testimony to the fact that Mewar was not only the land of the brave but also a seat of art and culture. Amidst aggression and bloodshed, literature and art flourished and creative pursuits of literature and artists did not suffer. Imagine, how glorious the period must have been when the Vijaya Stambha which is the sample of our great ancient architecture even today, was constructed. In the same fort, Kirti Stambha is standing high, reflecting how liberal the then administration was which allowed people from other communities and kingdoms to’ come and carry out construction work. It is useless to indulge in the debate whether the Vijay Stambha was constructed first or the Kirti Stambha. The fact is that both the capitals are standing side by side and reveal the proximity between the king and the subjects of Mewar.
5. The cycle of time does not remain the same. Where as the reign of Rana Sanga was crucial in raising the kingdom to the acme of glory, it also proved to be his nemesis. History took a turn. The fortune of Mewar the land of the brave, started waning. Rana tried to save the day with his acumen which was running against the stream and the glorious traditions for sometime.

On the basis of your understanding of the above passage answer each of the questions given below with the help of the options that follow:
(a) Maharana Pratap became immortal because:
(i) he ruled Mewar for 25 years
(ii) he added a lot of grandeur to Mewar
(iii) of his valour, sacrifice and patriotism
(iv) both (ii) and (iii)
(b) Difficulties in the way of Mewar were :
(i) lack of cooperation the nobility
(ii) ancient traditions of the kingdom
(iii) its small area and small population
(iv) the poverty of the subjects ‘
(c) During.thomy occasions:
(i) the flag of Mewar seemed to be lowered
(ii) the flag of Mewar was hoisted high
(iii) the people of Mewar showed gallantry
(iv) most of the rulers heaved a sigh of relief
(d) Mewar was lucky because : *
(i) all of its rulers were competent
(ii) most of its people were competent
(iii) most of its rulers were competent
(iv) only a few of its people were incompetent
Answer the following questions briefly:
(e) Who is the earliest King of’Mewar mentioned in the passage ?
(f) What was Rana Kumbha’s contribution to the glory of Mewar ?
(g) What does the writer find worth admiration in the people of Mewar ?
(h) How could art and literature flourish in Mewar ?
(i) How did the rulers show that they cared for their subjects ?
(j) What does the erection of Vijaya Stambha and Kirti Stambha in the same fort signify ?
(k) Find words from the passage which mean the same as each of the following :
(i) surprising (para 4)
(ii) evidence (para 4)
Answer. (a) (ii) be added a lot of grandeur to Mewar
(b) (iii) its small area and small population
(c) (i) the flag of Mewar seemed to be lowered
(d) (iii) most of its rulers were competent
(e) Bappa Rawal was the earliest king of Mewah
(f) Rana Kumbha had given a new stature to the kingdom through victories and development work. During his reign, literature and art also progressed extraordinarily. Rana himself was inclined towards writing and his works are read with reverence today.
(g) The people of Mewar are loving, cheerful, liberal, peaceful, prosperous and have pleasant nature. According to the writet, these are the qualities that make them worth admiration.
(h) During Rana Kumbha’s reign, literature and art progressed extraordinarily. The peaceful and prosperous atmosphere of his kingdom was suitable for the creation of high quality work of literatrure and art. The king himself countributed to literature. Even amidst wars and bloodshed literature and art flourished. .
(i) By building Vijaya Stambha and Kirti Stambha side by side, rulers revealed the proximity between the king and subjects of Mewar.
(j) Vijaya Stambha is the sample of our great ancient
architecture even today. Kirti Stambha reflects how liberal the then administration was which allowed people from other communities and kingdoms to come and carry out construction work.
(k) (i) astonishing (ii) testimony

Question.2. Read the passage given below:

1. To ensure its perpetuity, the ground is well held by the panther both in space and in time. It enjoys a much wider distribution over the globe than its bigger cousins, and procreates sufficiently profusely to ensure its continuity for all time to come.
2. There seems to be no particular breeding season of the panther, although its sawing and caterwauling is more frequently heard during winter and summer. The gestation period is about ninety to hundred days (Whipsnade, ninety-two days). The litter normally consists of four cubs, rarely five. Of these, generally two survive and not more than one reaches maturity. I have never come across more than two cubs at the heels of the mother. Likewise, graziers in the forest have generally found only two cubs hidden away among rocks, hollows of trees, and other impossible places.
3. Panther cubs are generally in evidence in March. They are born blind. This is a provision of Nature against their drifting away from the place of safety in which they are lodged by their mother, and exposing themselves to the danger of their being devoured by hyenas, jackals, and other predators. They generally open their eyes in about three to four weeks.
4. The mother alone rears its cubs in seclusion. It keeps them out of the reach of the impulsive and impatient male. As a matter of fact the mother separates from the male soon after mating and forgets all about their tumultuous union. The story that the male often looks in to find out how the mother is progressing with her cubs has ho foundation except in what we wish it should do at least.
5. The mother carries its cubs about by holding them by the scruff of their neck in its mouth. It trains them to stalk, and teaches them how to deliver the bite of death to the prey. The cubs learn to treat all and sundry with suspicion at their mother’s heels. Instinctively the cubs seek seclusion, keep to cover and protect their flanks by walking along the edge of the forest.
6. I have never had an opportunity to watch mother panther train its cubs. But in Pilibhit forests, I once saw a tigress giving some lessons to its little ones. I was sitting over its kill at Mala. As the sun set, the tigress materialised in the twilight behind my machan. For about an hour, it scanned and surveyed the entire area looking and listening with the gravest concern. It even went to the road where my elephant was awaiting my signal. The mahout spotted it from a distance and drove the elephant away.
7. When darkness descended upon the scene and all was well and safe the tigress called its cubs by emitting a low haa-oon. The cubs, two in number and bigger than a full- grown cat, soon responded. They came trotting up to their mother and hurried straight to the kill in indecent haste. The mother spitted at them so furiously that they doubled back its heels immediately. Thereafter, the mother and its cubs sat under cover about 50 feet (15 m) away from the kill to watch, wait, look, and listen. After about half an hour’s patient and fidgetless vigil the mother seemed to say ‘paid for’. At this signal, the cobs cautiously advanced, covering their flanks, towards the kill. No longer did they make a beeline for it, as they had done before.
8. The mother sat watching its cubs eat, and mounted guard on them. She did not partake of the meal.

On the basis of your understanding of the passage complete the statements given below with the help of options that follow:
(a) To protect its cubs the mother panther hides them :
(i) among rocks (ii) in the branches of the trees
(iii) behind the tree trunks (iv) at its heels
(b) The male panther :
(i) is protective of its cubs (ii) trains its cubs
(iii) watches the progress of the mother
(iv) is impulsive and impatient
Answer the following questions briefly:
(c) How many cubs does the mother panther rarely deliver ?
(d) What may happen if the panther cubs are not born blind ?
(e) Why did the mahaut drive his elephant away ?
(f) Why did the tigress spit at its cubs ?
(g) From the narrators observation what do we learn about the nature of the tigress ?
(h) Why does the panther not face the risk of extinction ?
(i) Find words from the passage which mean the same as
each of the following :
(i) moving aimlessly (para 3)
(ii) came down/fell (para 7)
Answer.
(a) (i) among rocks
(b) (iv) is impulsive and impatient
(c) The mother panther delivers litter of four cubs, rarely five.
(d) If the panther cubs are not blind they drift away from the place of safety in which they are lodged by their mother.
(e) The mahaut drove away his elephant to protect it from the tigress.
(f) The mother tigress spitted at it cubs to call them back to its heels and watch the prey carefully, instead of running towards it in haste.
(g) The tigress is very protective about her cubs. She rears them alone without the help of the male. She trains them to hunt and guards them, while they eat.
(h) The panther does not face the risk of extinction because it procreates sufficiendy and profusely to ensure its continuity for all time to come.
(i) Moving aimlessly-drifting
(ii) came down/fell-descend

Question.3. Read the passage given below :
People tend to amass possessions, sometimes without being aware of doing so. They can have a delightful surprise when they find something useful which they did not know they owned. Those who never have to change house become indiscriminate collectors of what can only be described as clutter. They leave unwanted objects in drawers, cupboards and attics for years in the belief that they may one day need them. Old people also accumulate belongings for two other reasons, lack of physical and mental energy, and sentiment. Things owned for a long time are-full of associations with the past, perhaps with the relatives who are dead, and so they gradually acquire a sentimental value.
Some things are collected deliberately in an attempt to avoid wastage. Among these are string and brown paper, kept by thrifty people when a parcel has been opened. Collecting small items can be a mania. A lady cuts out from newspapers sketches of model clothes that she would like to buy if she had money. As she is not rich, the chances are that she will never be able to afford such purchases. It is a harmless habit, but it litters up her desk.
Collecting as a serious hobby is quite different and has many advantages. It provides relaxation for leisure hours, as just looking at one’s treasure is always a joy. One doesn’t have to go out for amusement as the collection is housed at home. Whatever it consists of- stamps, records, first editions of books, china-there is always something to do in connection with it, from finding the right place for the latest addition to verifying facts in reference books. This hobby educates one not only in the chosen subject, but also in general matters which have some bearing on it.
There are other benefits also. One gets to meet like-minded collectors to get advice, compare notes, exchange articles, to show off one’s latest find etc. So one’s circle of friends grows. Soon the hobby leads to travelling, perhaps a meeting in another town, possibly a trip abroad in search of a rare specimen, for collectors are not confined to one country. Over the years one may well become an authority on one’s hobby and will probably be asked to give informal talks to little gatherings and then, if successful, to larger audiences.
(a) On the basis of your understanding of the above passage make notes on it, using headings and subheadings. Use recognisable abbreviations (wherever necessary – minimum four) and a format you consider suitable. Also supply an appropriate title to it.
(b) Write a summary of the passage in about 80 words.
Answer. (a) Title: Collection-Advantage or dis-advantage 1. Notes .
(i) Consequences
(a) PpL can hv delightful surprises
(b) Become indiscriminate collectors
(c) Senti values
(ii) Reaons
(a) To avoid wastage (b) Mania
(c) Lack of physical and mental energy in the case of old people.
(iii) Advantages
(a) Relaxation
(b) doesn’t hv to go out for amusement
(c) educates
(iv) Other benefits
(a) One may meet like-minded collectors
(b) frid circle grows
(c) hobby leads to travelling
Abbreviations Used
Hv have
Ppl people
Senti sentimental
Frnd friend
(b) Summary
People sometimes collect things due to various reasons which may be related to their need, lack of energy or sentimental value. Sometimes collection may be done to avoid wastage which later becomes mania. But it has many advantages too. It relaxes, amuses and educates. It has additional benefits where one may meet like-minded collectors to get advice, compare notes, exchange articles, to show off one’s latest find. As a result their friend circle grows bigger. In fact, hobby further leads to travelling.

SECTION B
(WRITING SKILLS)

Question.4. Principal, Sunrise Global School, Agra requires a receptionist for her school. Draft a suitable advertisement in about 50 words to be published in the classified columns of a national newspaper giving all the necessary details of qualifications and experience required in the receptionist.
OR
Water supply will be suspended for eight hours (10 am to 6 pm) on 6th of March for cleaning of the water tank. Write a notice in about 50 words advising the residents to store water for a day. You are Karan Kumar/Karuna Bajaj, Secretary, Janata Group Housing Society, Pal am Vihar, Kumool.
Answer.

OR

Question.5. Yesterday you went to Sunrise Hospital, Market Road, New Delhi taking with you the victin of a hit and run accident. There were chaotic conditions in the casualty department. The injured was attended to after a lot of precious time had been lost.
Write a letter of complaint in 120-150 words to the Medical Superintendent. You are Karan/Kauma, M114, Mall Road, Delhi. 
OR
Lack of job opportunities in the rural areas is forcing people to migrate to cities. Every big city thus has a number of slums in it. Life in these slums is miserable.
Write a letter in 120-150 words to the editor of a national newspaper on how we can improve the living conditions in these slums. You are Karan/Karuna, M 114, Mall Road, Delhi.
Answer.
M-l 14, Mall Road
Delhi
20th March, 20XX
The Medical Superintendent
Sunrise Hospital, Market Road
New Delhi
Subject: Chaotic conditions in the casualty department Dear Sir,
I, Karuna, a resident of New Delhi want to bring to your notice the conditions of the Sunrise hospital. Yesterday while I was going to my office I witnessed a person lying on the road in a pool of blood. There was crowd all around him. On enquiry I came to know that he was hit by an unidentified vehicle and no body took pain to take him to the hospital. So I brought him to your hospital where I was further shocked to see the pathetic condition of the casualty ward. The corridors were full of people where there was smell of medicines and cotton dabs were thrown away on the floor. I requested the doctor on duty to attend the patient immediately to avoid any mishap but was asked to file the police complaint first. The patient was Jeft unattended for about an hour during which he lost ample amount of blood which could have been proved to be fatal. Later when all the formalities were completed, the doctor came to see him and by God’s grace his life was saved. Then again drugs were administered in an inappropriate way by the staff who came only after being reminded. I think this negligence would cost anyone’s life someday. So I request you to be more vigilant towards the working of the hospital.
Yours truly
Karuna
OR
M-114, Mall Road
Delhi
20th March, 20xx
The Editor
Times of India
New Delhi
Subject: improvisation of the living conditions in slums Dear Sir,
Through the esteemed columns of your prestigious newspaper, I would like to highlight the quality of life of the people living in slums. Each family consists of six to seven members who share a single room. Their children can be seen playing on the heaps of garbage and breeding grounds of flies, mosquitoes and cockroaches. Sincere efforts are required to improve the physical, social and economic conditions of these slum dwellers.
Practical action should be taken by providing access to clean drinking water, proper health and sanitation facilities, waste management services and better housing facilities. Slum upgrading should be a major part of the government agenda to alleviate the poor living standards of the people.
But unless government takes action, there can be no sustainable solution to the housing challenges. Most of the governments are not doing much for this for a number of reasons which may include low incentives, less financial resources, lack of provision of any such reform due to their short term electoral period. But NGCs,training institutes, local residents, community groups can join hands together with government to eradicate the miseries of slum dwellers.
Hope my letter would find a place in your newspaper.
Yours Truly
Karuna

Question.6. ‘The policy of reservation of seats for admission to the professional course? is good for the deprived Sections of society.’
Write a debate in 150-200 words either for or against the motion.
OR
Write a speech in 150-200 words on ‘Benefits of early rising’ to be delivered by you in the morning assembly of your school. You are Karuna/ Karan, Head Girl/Head Boy.
Answer . ‘Policy of reservation of seats to the professional courses’
Good morning, respected judges and the esteemed audience. The topic of today’s debate is ’Policy of reservation of seats to the professional courses’. I, Karuna stand before you to speak against the motion.
According to the Indian constitution, reservation in all the fields whether education, jobs or any other place, has been made to bring under previleged classes at par with privileged or general ones. There are numerous reservations like reservation for women, reservation for physically challenged; reservation for economically backward class, reservation for scheduled castes, etc. But I believe that this leads to further discrimination in the society. It had started with a very good objective of uplifting the socially backward society to give them equal opportunities. But with time its meaning has been changed and the aim of starting it lost. People are taking undue advantage of it. This has resulted in widespread protests and counter protests as. it has affected thousands of job and admission opportunities. The students securing 80 or 90 percent sometimes lag behind the underprivileged who secure only 40 or 50 percent for taking admission in the vocational or professional courses. It denies the equality of opportunity to those who not belong to backward communities. They are denied admissions even though they have secured good percentage. This would also perpetuate caste feeling among people and hamper national unity. Also the reservation system in India is creating a manpower which is not able to compete at the global level. India needs people who can work for the growth and development but reservation is raising undeserving candidates at higher positions. So I think reservation system should be demolished.
OR
‘Benefits of early rising’
Honorable Principal,respected teachers and dear friends, Good Morning! I am Karuna, Head Girl of the school; it is a great opportunity for me to share my views on the topic ‘Benefits of early rising’ in today’s assembly.
We derive pleasure from many things, people, and places in our life. One such pleasure is when we get up early in the morning. It gives a good start to our day’s work. The air we breathe is so fresh that it refreshes our whole day. One should not miss the wonderful art of nature- the rising of sun from the dark color of midnight and gradually turning brighter, spreading its vibrant colors in the sky. This glory can’t be explained in words. We come into close contact with nature when we hear the chirping of birds, raw green trees, flowers and leaves dancing. There is no chaos in the early morning and we can easily concentrate on our studies. It is well said that whatever we learn in the early hours is learnt quickly and our mind retains that forever. Early morning meditation helps in keeping our body and soul fit. Breakfast, the most important meal of the day can be taken up timely. Besides many other things, one may get enough time to exercise which keeps the body energetic and fit throughout #the day. Then our productivity and capacity to do work also increases. There is no distraction in the morning hours in case we want to indulge in some creative writing. To sum up, I can say that I have full faith in the saying, “Early to bed, early to rise, makes a man healthy and wise.

Question.7. India is a land of diversity. One way in which it makes us feel proud of it is the number of festivals we enjoy. Write an article in 150-200 words on ‘Festivals of India’. You are Karuna/Karan.
OR
Rising pollution, fast and competitive lifestyle, lack of nutritious food etc. have caused health woes for a large section of our population. Providing health care used to be a charitable and ethical activity. Tpday it has become commercialized, a money spinning business. Write an article in 150-200 words on How to provide proper health care to the common man’. You are Karan/Karuna.
Answer. ‘Festivals of India’
By Karuna
India is a land of colors. It is a country populated by the people of many castes, religions, faiths, communities, languages and creeds. Therefore, many festivals, celebrations, social and cultural gatherings, fairs take place every year. India is said to be a country which is full of pleasures, joys and festivities. Throughout the year we celebrate many festivals. They represent the grandeur of the country. These are the occasions when families gather at one place and celebrate happy moments. Festivals are-celebrated throughout the year and people await these festivals with great enthusiasm. These have an important . place in the hearts of Indians as they believe that the fasts on these occasions purify their soul and help them lead a problem free life. Some festivals are celebrated all over India and people celebrate them irrespective of their status and social position. These include Diwali, Holi and Dusshera. Each festival has its religious value and contains some mythology behind it. For example, Dusshera is celebrated on account of victory of good over evil and when God Ram killed Ravana. Similarly, Janmashtami has also a social and religious significance as Lord Krishna was born to kill all the demons fron the earth. Thus, each and every festival has its own value which teaches people to come closer and forget all their differences.
OR
‘How to provide proper healthcare to the common man’
By Karuna
A large section of our population is suffering from the physical as well as mental problems like illness, fever, injury, epilepsy, learning disability, etc. Women have problems related to pregnancy and childbirth, children do require immunization against common diseases. Most of these health woes have been the result of our changing life style, rising pollution, Tack of nutrition value in food. Hence, they require access to health care facilities and treatment. Unfortunately, health services are often planned without consulting the community members. To meet the necessities of the people for accessible, affordable services, community members should be consulted and involved in their planning. Health centers should be more vigilant. Most people prefer home remedial measures and go to the hospital or refer to a doctor only when the situation is beyond their control. But it’s not necessary that they go to a well-qualified doctor, they may approach local pharmacist or traditional healers. Therefore, it is necessary that the health sector must intervene and create awarness among the people. Health care facilities should be within the reach of common man. Government’s investment in public health care is very low. As a result, many hospitals run by the government do not provide sufficient medical facilities. Therefore improvements are required in . this sector and it is a positive thing that the government is now planning to allocate more funds for the renovation of hospitals.

SECTION — C
(Literature : Text Book and Long Reading Text)

Question.8. Read the extract given below and answer the questions that follow:
Its loveliness increases, it will never
Pass into nothingness; but will keep
A bower quiet,for us, and a sleep
Full of sweet dreams, and health, and quiet breathing.
(a) Whose loveliness will keep on increasing ?
(b) Identify the phrase which says that ‘it’ is immortal:
(c) What is a ‘bower’ ?
(d) Why do we need sweet dreams, health and quiet breathing in our lives ?
OR
Old
familiar ache, my childhood’s fear,
but all I said was, see you soon,
Amma,
all I did was smile and smile and
smile…………….
(a) What does the phrase, ‘familiar ache’ mean ?
(b) What was the poet’s childhood fear ?
(c) What do the hirst two lines tell us about the poet’s feelings for her mother ?
(d) What does the repeated use of the word, ‘smile’ mean ?
Answer . (a) Loveliness of anything that is beautiful keeps on increasing. It gives us immense joy,unending and everlasting pleasure.
(b) “It will never pass into nothingness” is the phrase which says that it is immortal.
(c) “Bower” literary means leafy shelter which here refers to the sweet dreams which consists of all beautiful objects that revive during our sleep when we are tired or troubled. We love to relive these joyous memories.
(d) We need sweet dreams, health and quiet breathing in our lives as they refresh us and give eternal joy and remove our sorrows and sufferings. Thus, we want to remain bound to the earth.
OR 
(a) By the phrase familiar ache’ the poet means the pain which she had already felt in her childhood. The pain was due to the fear of getting separated from her mother and the realization that she had not cared for her. She suppressed it by smiling again and again at her and promising to meet her soon.
(b) The poet’s childhood fear was that as her mother was old and had pale and colorless face, she might not live very long and that she might lose her someday.
(c) The poet had the childhood fear that she would lose her mother soon. She possessed the same fear while going away from her. But she did not say anything to her except the optimistic note ‘see jou soon Amma’. She gave her a cheerful farewell.
(d) The word ‘smile’ has been repeated to show that in order to drive her fearful thought of separating from her mother, she puts on a false smile. Secondly, she gives moral support to her mother by promising to meet her soon. She tries to hide her feeling by smiling again and again.

Question.9. Answer any four of the following in 30-40 words each:
(a) Describe the irony in Saheb’s name.
(b) Why was Gandhiji opposed to C.E Andrews helping him in Champaran ?
(e) When he was only ten days old, a prediction was made about the future of the Tiger King. What was ironic about it?
(f) What was his father’s chief concern about Dr. Sadao ?
Answer . (a) Saheb’s full name was Saheb-E-Alam means the ‘Lord of the Universe’. The irony in his name was that he was a poor rag picker who did not even have the chappals to wear. He walked on the streets barefooted to earn his living and looked into the garbage for gold coins or something to survive his days.
(b) Gandhiji was opposed to C.F. Andrews helping him in Champaran because he wanted the Indians to be self-dependent and self-reliant in their struggle against injustice. He told him that Indians were strong enough to fight their own battle and had the capability to win it. Therefore, Gandhiji refused his help.
(e) When The Tiger King’ was only ten days old, the chief astrologer predicted that the death of the prince would result from a tiger. So when he grew up, he killed hundred tigers without knowing that the hundredth tiger didn’t die of his bullet. Ironically, the King died because of a wooden toy tiger.
(f) Sadao’s education had been his father’s chief concern. At the age of twenty two, he sent his son to America to learn about surgery and medicine. He came up to his father’s expectations. By the time his father died. Sadao had established himself as a famous surgeon as well as a scientist.

Question.10. Answer the following question in 120-150 words:
Our language is part of our culture and we are proud of it. Describe how regretful M. Hamel and the village elders are for having neglected their native language, French.
OR
Teachers always advise their students to dream big. Yet, the same teachers in your classrooms find built with Sophie when she dreams. What is wrong with Sophie’s dreams ?
Answer. There is no doubt that our language is a part of our culture and we feel proud of it. But the true value of it can be realized only when the freedom of speaking it, is taken away from us.
The story ‘The Last Lesson’ depicts the pathos of the whole situation, how people feel in not learning their language and losing an asset in M. Hamel. One day Franz, oneofthe students came unwillingly to the school and noticed that everything was still and as quiet as Sunday morning. There was an order from Berlin that French would not be taught furthermore in the schools a/id instead German was to be taught. This news shocked everyone. All the villagers gathered in the classroom to attend their last French lesson and to mark their respect for the French teacher, M. Hamel, who was going to deliver his last speech in French. They sat on the back benches with the students. They felt sorry that they had not attended the school. And thanked Hamel for his faithful service.
To honor his French lesson, M. Hamel also put on his fine Sunday clothes. His behavior changed to kindness. He told his students that it was the most beautiful and logical language and they should not forget it.
OR
It is a natural thing for teenagers to dream. They don’t have much liabilities and burden at this stage of life so they are free to dream. It is a part of their life but sometimes these dreams are impractical and non-realistic and when they are shattered, they cause a lot of pain.
In the story ‘Going Places’, the author has described the feelings and dreams of a girl, Sophie, who was a school-going teenager. She was a day dreamer and fantasizes that she had met with “Danny Casey, a football player from Ireland. She dreamt of having met him twice in the arcade. For her, he was hero to be worshipped. She went to the place where she thought he would meet her and when he didn’t turn up she felt disappointed. Then she thought of owning a boutique, becoming a manager, a fashion designer or an actress irrespective of thinking about her socio economic status.She had no thought about where the money would come for opening a boutique. She was blind to the bitter truth of life. She dreamt of an imaginary life, full of beautiful things. It can be said that she wanted to lead a lavish and grand life which was not possible. She was over ambitious. Her dreams were unrealistic in the sense that ultimately she would have to work in a biscuit factory.

Question.11. Answer the following question in 120-150 words :
Deny sneaked into Mr. Lamb’s garden and it became a turning point in his life. Comment.
OR
How did Jo want the Roger Shunk story to end ? Why?
Answer. Derry sneaked into Mr. Lamb’s garden and it became a turning point in his life. Before that Derry used to live an isolated life. He did not like meeting with people or socializing. The reason was his burnt face, seeing which the people often got terrified. He began leading a secluded life.
Meeting Mr. Lamb brought a change in his life.His attitude I towards life was completely changed. Mr. Lamb gave him
confidence and supported him morally as he was physically i impaired like him. He had a tin leg because the original one was blown off in the war. He told Derry that he was not affected
I by the people’s sarcastic remarks. He motivated Derry to face
I the challenges of life and not to lament over his burnt face,
According to him, he was lucky to have two arms, two legs, ears, eyes and tongue. He could do far better than others.
All these preaching left an impression on Derry and now he started looking at things and world differently. He began to help Mr. Lamb with crab apples and developed a positive attitude towards life.
OR
Jack used to tell his little daughter Jo bedtime stories. As soon as she grew older, she began to ask questions from her father. Once her father told her a story of a little animal called Skunk who smelled awfully bad. He therefore met with a wizard who solved his problem with magic wand and made him smell like
roses. But Skunks mother did not like it and took him back to the wizard to smell awfully bad once again.
This ending was not acceptable to Jo as she wanted the story to have another end in which the wizard should hit the mommy with his magic wand and chopping off her arms ‘forcibily’ Jo thought that Roger was the hero of the story so he must not look ugly or stinky. Jo’s perspective on life was different from her father’s. She wanted to change the end of the story to assert her views on het father. She had her own ideals and views which she wanted to be pursued.

Question.12. Answer the following question in 120-150 words 
What do we learn about Mrs. Hall and Griffin from their first interaction at Coach and Horses inn ?
OR .
What kind of life did Silas lead before coming to Raveloe ?
Answer . Mrs. Hall was the owner of the inn ‘Coach and Horses’. She was a friendly woman who socialized with her guests easily. She was very excited when Griffin came to stay at her inn as she was not expecting anyone in such a harsh winter. She tried to be the best host. Although she was rebuked by Griffin many times when she tried to help him with his coat and hat, she did not give up. She attributed his behavior to an accident which he had met. She was a curious woman who wanted to know -what had happened to him and why was he wearing the bandages all over his face. She showed her full sympathy to him and tolerated him as he was paying a handsome sum as rent. It can be concluded that she was a credulous, somewhat irresponsible (in believing the stranger even without confirming his identity) about her family’s well-being
Griffin was a man without any humanity. He was a gifted young student,but he misused his talent and knowledge. He found Mrs. Hall’s inn the suitable place to carry on with his experiments. But he was not interested in advancing any conversation with Mrs. Hall. We can say that he was very rude towards her. He kept all his intentions and designs to himself. He had a mysterious nature. He didn’t want anyone to know his secret mission. He did not have any regard for relations and society.
OR
Silas had come to Raveloe fifteen years earlier from a city to the North. Before that he was a faithful member of a religious sect in the Lantern Yard. He had been an exceptionally bright and fervent young disciple. The religious community had a great regard for him. His fits were regarded there as a mark of special closeness to the Holy spirit. He hadfull faith in humanity and God. He was a simple man who wanted to live within himself or in other words he was an introvert. He had a close friend named William Dane, and he was engaged to a serving girl, Sarah. Later on he is betayed by William who accusses him of theft unjustly and marries Silas, fiancee. As a result he loses faith in God and settles in Raveloe.

Question. 13. Answer the following question in 120-150 words :
Everyone who conies into contact with Griffin suffers. Attempt a character sketch of Griffin in the light of this remark,
OR
Attempt a character sketch of Nancy Lammeter.
Answer. Griffin is the protagonist of the novel. The Invisible Man actually, was a scientist who was doing experiments to change a human being into invisible man by changing the refractive index of human body. He proved to be the trouble to whomsoever he came in contact with. First, it was his father who became his victim. He robbed him which drove him to commit suicide. Then he carried on his experiments of converting a human body into invisible on the neighbour’s cat. On being caught by his landlord and in order to hide from . him, he set his building on fire. He stole clothes from a theatre shop and then dodged Mrs. Hall, the owner of the inn ‘Coach and Horses’. There also when his progress slowed down and he needed more money to pay the ’bill to the pub owner, he burgled the house of Reverend Bunting.
He asked for help from a tramp, Mr. Thomas Marvel who assisted him many times but he proved to be cleverer than Griffin and ran away with Griffin’s stolen money. Griffin followed him to the town of Burdock where he met his old schoolmate, Dr. Kemp. He tried to take him in confidence and asked him to be his partner in ‘Reign of Terror’ to which Kemp refused. So Griffin thought of killing him,in order to take the revenge but didn’t succeed. Although he became the victim of circumstances but he remained troublesome for everyone who came in contact with him.
OR
Nancy was a pretty woman who did not change at all in the past sixteen years. She was a good country girl who came from a wealthy family of Raveloe. As a young girl she was very charming and graceful.Her maturity was reflected through the truthful glance of her eyes. She was a pure hearted person. She had high and strict principles. She did not care to be associated with any person of poor reputation. She lived her life according to her own. She proved to be a loving and caring wife who was fully satisfied with her married life. She was not willing to adopt a child but she even didn’t want to disappoint Godfrey, her husband. When she came to know that Eppie was her husband’s real daughter she showed love and sympathy to her rather than disapproving or rebuking Godfrey. She respected the village customs and was responsible for taking up duties as the mistress of Red House when Godfrey was following the departing congregation. She was not too much sophisticated or educated. After marrying Godfrey, her life became organized and purposeful. She found peace and satisfaction in her life and wanted to continue the same for the rest of her life only.

SET II

Note : Except for the following questions, all the remaining questions have been asked in previous sets.

SECTION — B
(WRITING SKILLS)

Question.4. You need to buy a flat. Draft a suitable advertisement in about 50 words to be published in the classified columns of a local newspaper giving all the necessary details of your requirement. You are Karan/Karuna, M 114, Mall Road, Delhi. 
OR
Sunrise Global School, Agra is going to organize a one- act play competition in the school auditorium. You have decided to invite noted stage artiste, Nalini to grace the occasion. Draft a formal invitation for her in about 50 words. You are Karuna/Karan, Cultural Secretary.
Answer.

OR
Sunrise Global School Agra
15th May, 2016.
Nalini
Abhilasha Vihar
Delhi
Subject: Invitation to preside over one-act play competition. Dear Ma’am,
Our school is going to organize a one-act play competition in the school auditorium. A number of students are likely to participate in this competition. We shall be highly honored if you will grace the occasion with your presence on the 30th of June, 2016 at 2 pm. ”
R.S. V.P .
Karan
(Cultural Secretary)
Sunrise Global School
Agra

Question.5. Park Lane, Chanakyapuram, Mysore is proud of having four reputed public schools in close proximity to each other. In the morning and afternoon there is a heavy traffic along the road and hundreds of student are put to a lot of inconvenience.
Write a letter in 120-150words to the Deputy Commissioner of Police (Traffic) describing the problem. Suggest a few measures to regulate the traffic. You are Karuna Shetty/ Karan Kumar, Principal, Sunrise Global School.
OR
Write an application (including a resume) in 120-150 ‘ words for the post of receptionist advertised in a national newspaper by JKL Publishers, Peshwa Road, Pune. You are Karuna, M 114 Mall Road, Pune, a graduate from SNDT University and have done a Secretarial Practice Course from YWCA, Mumbai.
Answer.
Sunrise Global School,
Park Lane, Chanakyapuram,
Mysore .
1st March, 2016
The Deputy Commissioner of Police (Traffic) Chanakyapuram,
Mysore
Dear Sir/Madam,
Subject: Traffic congestion on the road surrounding schools.
I wish to bring to your attention the poor traffic management on the road surrounding schools, which causes great inconvenience. There are four reputed public schools in the ambit of the area. In the morning, the movement of the school transport, staff vehicles and the vehicles of the parents, who come to drop their children, along with the general traffic, creates a huge chaos on the road. The same chaos could be witnessed in the afternoon. The situation gets worse when .the traffic lights don’t work. The children, who come from the nearby areas, find it difficult to cross the roads and face huge risk. The, safety of the children is of utmost importance for the schools. I would request you to please avoid traffic police on different points of the roads around the schools, so as to avoid traffic jams. Also, a regular check of the traffic lights would help in reducing inconvenience. The schools are also planning to.arrange traffic rules awareness workshop for their respective staff, parents and children. I request you to look into the matter and solve the issue at the earliest.
Yours Sincerely Karan Kumar (Principal)
Sunrise Global School
OR
Ml 14, Mall Road
Pune
1st March, 2016
JKL Publishers Peshwa Road
Pune
Subject: Application for the post of Receptionist.
I have done my graduation from SNDT University and a Secretarial Practive Course from YWCA, Mumbai. I have been working as a receptionist with Gupta & Sons Textilies Ltd. since March, 2014. I have proven record of meeting my goals by accepting all challenges throughout my professional career.
My resume has been attached herewith. If I can provide you with any further information regarding my background and qualifications, please let me know.
I will be looking forward to hear from you soon.
Yours faithfully,
Karuna .
Enclosure : Resume and two passport-size photographs
RESUME
Name: Karuna
Father’s Name : Om Prakash Chauhan
Date of Birth: 11-07-1989
Residential Address : Ml 14, Mall Road, Pune
Contact Number : +91 -xxxxxxxxxx
Educational Qualifications : (i) Graduation (SNDT University)
(ii) Secretarial Practice Course (YWCA, Mumbai)
Computer Proficiency : MS Office and Adobe Photoshop.
Experience : Working as Receptionaist with Gupta & Sons Textites Ltd. since March 2014
Salary Expected : Rs. 15,000
Material Status : Unmarried
Hobbies : Traveling, reading and socializing
Languages Known : Hindi and English

Question.6. ‘Rising prices can be controlled only by the government.’
Write a debate in 150-200 words either for or against the motion.
OR
Write a speech in 150-200 words on the topic, ‘Library plays an important role at school’. It is to be delivered in the morning assembly. You are Karuna/Karan, Head Girl/
Head Boy.
Answer. ‘Rising prices can be controlled only by the government’
A very good morning to jury members, friends and my fellow opponents. I am Karuna of Std. XII and today, I am going to speak against the motion on the topic ‘Rising prices can be controlled only by the government.” The role of government in an economy, is to announce measures of regulation and control. A government can impose restrictions on hoarding, the export of some items and track prices of limited commodities. However, the execution vests in the custody of the people residing the nation.
It would not be correct to put the blame wholly on the government. The consumer is no less to be blamed for inflation.
Some consumers allow themselves to be robbed for fear of a good supply position and consistently adverse price trends.
Such practices not only deprive the country of much-needed resources but also serve as bad examples for those who cannot afford to pay such high prices. By reducing the demand of a good, its price can be controlled by the consumers, Rising prices or inflation can be controlled by the combined effort of the government and consumers.
Thank you.
OR
Library plays an important role at school Good morning everyone!
Respected Principal teachers and my dear friends, I Karuna, the Head girl of your school, is going to give a short speech on ‘Library plays an important role at school.’ A school library is a place that plays an important role in encouraging innovation and thirst for knowledge. It provides support for learning and teaching throughout the school. The school library exhibits positive impact on the academic, achievement of the student, as it helps in developing the mind of the student. It is integral to the teaching and learning process. ‘
A library at school not only provides academic references but a wide range of fiction, non-fiction, digital, print resources.
It develops the habit of reading for pleasure and to enhance students intellectual, cultural and emotional growth. The school library also provides opportunities to teachers to plan, implement, and evaluate new learning programs. It also plays a critical role in assising the students in compiling, critically analysing and organising information, and then communicing their findings. A school library provides a safe environment that encourages curiosity and imagination. The students become users of information and start to develop a better understanding of the world.
Thank you

SET III

Note : Except for the following questions, all the remaining questions have been asked in previous Sets.

SECTION —B
(WRITING SKILLS)

Question.6.‘The policy of no detention till class VIII is > not in the interest of students.’ Write a debate in 150-200 words either in favour of or against the motion.’
OR
Write a speech in 150-200 words on the topic, ‘A student must know how to manage his time.’ It is to be delivered in the morning assembly. You are Karan/Karuna, Head Boy/ Head Girl of the school.
Answer. A very good morning to jury members, friends, and my fellow opponents. Today, I am going to speak for the motion ‘The policy of no detention till class 8 is not in the interest of the students.’ Firstly, let me tell you what the no-detention policy states. The article states that no child shall be held back in any class or expelled from school till the completion of elementary education. The step was taken to reduce stress and pressure among students, but the policy has led to poor outcomes, as there has hardly been any improvement in the academic standard. It has encouraged negligence and reluctance of children to study. A student develops a carefree and an easy going attitude, with an automatic promotion system up to class 8, and in class 9 he is unable to change his attitude suddenly.
They fail to cope up with the academic pressure and end up doing badly in board exams.
I, therefore, firmly agree that the policy of no detention till class 8 is not in the interest of students, as it gives security of passage to the next class, regardless of a child’s competence to learn higher concepts.
OR
A student must know how to manage his time Here are a few points that will help you in framing your answer,

1.  When life takes a highway and everything seems to be going out of control, the only thing that can bring back the required place in life is time management.
2. Because a students time is so valuable, it is important to use it wisely. This can be done by taking advantage of an idle time that could be spent studying: This could happen during lucnh, on the bus ride to and from school or before A class starts.
3. A student must prioritize what comes first in his life. If a job starts to interfere with school, a student might need to change his work schedule or find a different job.
4. Spending time with friends, family and having fun is
   important to provide a healthy balance. To successfully satisfy their personal life and meet education obligations, students must learn to juggle the two effectively by managing time well.
5. When you get into the habit of procrastinating as a student, you tend to do the same as an adult. Habits that are learned when young are hard to change the older you become. Therefore, develop a sense of responsibility towards your task.

Question.7. India is an emerging economy, We are rich in natural resources. Yet a significant proportion of our people is living below poverty line. One cause of this poverty is our rising population.
Write an article is 150-200 words On ‘How to keep a check on population.’ You are Karuna/Karan.
OR
Women feel unsafe on the road, at their place of work and even at home. There is an urgent need to change the male mindset in its attitude towards women.
Write an article in 150-200 words on ‘How to make women feel safe’. You are Karan/Karuna.
Answer .
How to keep check on population
By Karuna
‘ An economy requires the support of its population to function smoothly. The fact remains intact that India is extremely rich in its natural resources, yet incapable of sustaining its population.
We often ponder over the question. Who is responsible for the imbalance ? Is it the current government ? Is it the lack of facility ? Or is just ignorance ?
The disproportionate distribution of wealth in the country is mostly an outcome of the humongous population, hyperbolically termed as the ‘Population Explosion’. The government, at regular intervals, has introduced birth control schemes and programmes, such as ‘Hum Do Hamare Do’. Such programs have failed tremendously because of the illiterate and religiously guided notions of the people. The only way possible to curb the population is to educate thq Indian population. The beliefs and desirability of having a male child also increases the population, which can be checked by understanding that it is better to facilitate the children in a manner to empower them.
The government can work effectively only when the population understands the fragility and need of the moment.
OR
Here are some points that will help you in framing your answer.

1. We must start to bring up our boys like we bring up our girls, we must teach them respect and empathy for another human being
2. Have severe laws to deal with eve teasers, rapists and molesters
3. Domestic violence against women must not be tolerated implementation of laws has to be quick
4. Give equal opportunities of education and employment to women ‘
5. Teach our girls and women self-defence techniques ‘ increase security at public places
6. Employ special forces at tourist spots to ensure the security of foreign and domestic women tourists

Question.9. Answer any four of the following in 30-40 Words each:
(a) How did his experience at the YMCA swimming pool affect Douglas ?
(b) What hospitality did the peddler receive from the crofter ?
(c) What kind of life was enjoyed by crown prince Jung Bahadur till he reached the age of twenty ?
(d) Where, when and how did Dr. Sadao meet Hana ?
Answer. (a) The experience created a terrible fear in the heart
of Douglas for a long time. This made Douglas all the more afraid of water. The very sight of water made him ill. Douglas decided against playing any water sports.
(b) Unlike the indiferent attitude of the others towards him, the peddler was whole heartedly welcomed by the crofter in his cottage. The crofter at once put the porridge pot on the fire and gave him supper. He gave him a roll of tobacco for his pipe. He also played the game of cards with him.
(c) The British dominance and its effect on the Indian , royalty i? evident in the upbringing of the crown prince Jung Bahadur. He was brought up by an English nanny, drank the milk of an English cow, taught English by an Englishman and saw nothing but English films.
(d) Dr. Sadao met Hana in America af the house of a professor where some foreign students were living. He liked her but waited to fall in love with her untill he was sure she was a pure Japanese.

CBSE previous Year Solved  Papers  Class 12 English Outside Delhi 2013

Time allowed : 3 hours                                                                                           Maximum Marks: 100
General Instructions :

1. This paper is divided into three sections : A, B and C. All the sections are compulsory.
2. Separate instructions are given with each section and question, wherever necessary. Read these instructions very carefully and follow them faithfully.
3. Do not exceed the prescribed word limit while answering the questions.

SET I

SECTION – A
(Reading)

Question.1. Read the passage given below and answer die questions
that follow:

1.  Air pollution is an issue which concerns us all alike. One can willingly choose or reject a food, a drink or a life comfort, but unfortunately there is tittle choice for the air we breathe. All that is there in the air is inhaled by one and all living in those surroundings.
2. Air pollutant is defined as a substance which is present in an amount exceeding the normal concentrations. It could either be gaseous or a particulate matter. The important and harmful polluting gases are carbon monoxide, carbon dioxide, ozone and oxides of sulphur and nitrogen. The common particulate pollutants are the dusts of various inorganic or organic origins. Although we often talk of the outdoor air pollution caused by industrial and vehicular exhausts, the indoor pollution may prove to be as or a more important cause of health problems.
3.  Recognition of air pollution is relatively recent. It is not uncommon to experience a feeling of ‘suffocation’ in a closed environment. It is often ascribed to the lack of oxygen. Fortunately, however, the composition of air is remarkably constant all over the world. There is about 79 percent nitrogen and 21 per cent oxygen in the air – the other gases forming a very small fraction. It is true that carbon dioxide exhaled out of lungs may accumulate in a closed and over-crowded place. But such an increase is usually small and temporary unless the room is really air-tight. Exposure to poisonous gases such as carbon monoxide may occur in a closed room, heated by burning coal inside. This may also prove to be fatal.
4. What is more common in a poorly ventilated home is a vague constellation of symptoms described as the sick-building syndrome. It is characterized by a general feeling of malaise, head-ache, dizziness and irritation of mucous membranes. It may also be accompanied by, nausea, itching, aches, pains and depression. Sick building syndrome is getting commoner in big cities with the small houses, which are generally over¬furnished. Some of the important pollutants whose indoor concentrations exceed to those of the outdoors include gases such as carbon monoxide, carbon dioxide, oxides of nitrogen and organic substances like spores, formaldehydes, hydrocarbon aerosols and allergens. The sources are attributed to a variety of construction materials, insulations, furnishings, adhesives, cosmetics, house dusts, fungi and other indoor products.
5.  By-products of fuel combustion are important in houses with indoor kitchens. It is not only the burning of dried dung and foelwood which is responsible, but also kerosene and liquid petroleum gas. Oxides of both nitrogen and sulphur are released from their combustion.
6.  Smoking of tobacco in a closed environment is an important source of indoor pollution. It may not be “high quantitatively, but significantly hazardous for health. It is because of the fact that there are over 3000 chemical constituents in tobacco smoke, which have been identified. These are harmful for human health.
7.  Micro-organisms and allergens are of special significance in the causation and spread of diseases. Most of the infective illnesses may involve more persons of a family living in common indoor environment. These include viral and bacterial diseases like tuberculosis.
8.  Besides infections, allergic and hypersensitivity disorders are spreading fast. Although asthma is the most common form of respiratory allergic disorders, pneumonias are common, but more persistent and serious. These are attributed to exposures to allergens from various fungi, molds, hay and other organic materials. Indoor air ventilation systems, coolers, air- conditioners, dampness, decay, pet animals, production or handling of the causative items are responsible for these hypersensitivity – diseases.
9. Obviously, the spectrum of pollution is very wide and our options are limited. Indoor pollution may be handled relatively easily by an individual. Moreover, the good work must start from one’s own house.

(a) (i) What is an air pollutant ?
Answer : Air pollutant is defined as a substance which is present in the air while normally, it is not present in an amount exceeding the normal concentrations.
(ii) In what forms are the air pollutants present ?
Answer : Air pollutants are present in gaseous form such as carbon monoxide, carbon dioxide, ozone and oxides of sulphur and nitrogen. The pollutants are also in the form of dust of various inorganic or organic origins.
(iii) Why do we feel suffocated in a closed environment ?
Answer : We feel suffocated in a closed environment due to lack of oxygen. Accumulation of carbon dioxide exhaled out of lungs and exposure to carbon monoxide are also the reasons of suffocation.
(iv) What is sick building syndrome ? How is it increasing ?
Answer : Sick building syndrome is characterized by a general feeling of malaise, headache, dizziness and irritation of mucous membrane. It may be accompanied by nausea, itching, aches, pains and depression.
It is increasing due to poorly ventilated and over furnished houses in big cities in which there is high Concentration of carbon dioxide, carbon monoxide and oxides of nitrogen and other harmful substances.
(v) How is indoor smoking hazardous ?
Answer : Indoor smoking is hazardous in the way that there are 3,000 chemical constituents in tobacco smoke which are harmful for human health.
(vi) How can one overcome the dangers of indoor air pollution?
Answer : The houses should be properly ventilated with more and more greenery around them. Smoking of tobacco and burning of coal inside the houses should also be avoided to overcome the dangers of indoor air pollution.
(b) Find the words from the above passage which mean the same as the following:
(i) Giddiness (para 4) 
Answer: Dizziness.
(ii) Constant (para 8)
Answer: Persistent.
(iii) Humidity (para 8)
Answer: Dampness.

Question.2. Read the passage below and answer the questions that follow:
The term dietary fibres refers collectively to’ indigestible carbohydrates present in plant foods. The importance of the these dietary fibres came into the picture when it was observed that the people having diet rich in these fibres, had low incidence of coronary heart disease, irritable bowel syndrome,’dental caries and gall stones.The foodstuffs rich in these dietary fibres are cereals and grains, legumes, fruits with seeds, citrus fruits, carrots, cabbage, green
leafy vegetables, apples, melons, peaches, pears etc.
These dietary fibres are not digested by the enzymes of the stomach ‘and the small intestine whereas, most of the other carbohydrates like starch and sugar are digested and absorbed. The dietary fibres have the property of holding water and because of it, these get swollen and behave like a sponge as these pass through the gastrointestinal tract. The fibres add bulk to the diet and increase transit time in the gut. Some of these fibres may undergo fermentation in the colon.
In recent years, it has been considered essential to have some amount of fibres in the diet. Their beneficial effects help in preventing coronary heart disease, and decreasing cholesterol levels. The fibres like gums and pectin are reported to decrease’ postprandial (after meals) glucose level in blood. These types of dietary fibres ate recommended for the management of certain types of diabetes. Recent studies have shown that the fenugreek (Methi) seeds, which contain 40 per cent gum, are effective in decreasing blood glucose and cholesterol levels as i compared to other gum containing vegetables.
Some dietary fibres increase transit time and decrease the time of release of ingested food in colon. The diet having less fibres is associated with colon cancer and the dietary fibres may play a role in decreasing the risk of it.
Theidietary fibres hold water so that stools are soft, bulky and readily eliminated. Therefore high fibre intake prevents or relieves constipation.
The fibres increase motility of the small intestine and the colon and by decreasing the transit time there is less time’ for exposure of the mucosa to harmful toxic substances. Therefore, there is a less, desire to eat and the energy intake can be maintained within the range of requirement. This phenomenon helps in keeping a check on obesity Another reason in helping to decrease obesity is that the high-fibre diets have somewhat lower coefficients of digestibility.
The dietary fibres may have some adverse effects on nutrition by binding some trace metals like calcium, magnesium, phosphorus, zinc and others and therefore preventing their proper absorption. This may pose a possibility of nutritional deficiency especially when diets contain marginal levels of mineral elements. This may become an important constraint on increasing dietary fibres. It is suggested that an intake of 40 grams dietary fibres per day is desirable.
(a) On the basis of your reading of the above passage, make notes in points only, using abbreviations wherever necessary. Supply a suitable title.
Answer:
Tide: Dietary Fibres
1. Notes
(i) Importance: lowers
(a) hrt disease
(b) irrtble bowel syndrome
(c) dental caries
(d) gall stones
(ii) Rich dietary fibers
(a) cereals, grains, legumes (b) fruits
(c) vegetables
(iii) Adverse effects
(a) bind metals like ca, mg, ph, zn
(b) prevents their absoptn
(c) nutnl defcncy

(b) Write a summary of the above in about 80 words.  Summary: Dietary fibers are indigestible carbohydrates present in plant foods. People having diet rich in fibers have low heart diseases, irritable bowel syndrome, dental caries and gall stones. Sources of dietary fibers are legumes, cereals, fruits, vegetables and grains. The fibers like gums present in fenugreek and pectin decrease glucose level. The diet which is less in fibers results in colon cancer. The dietary fibers hold water and functions like sponge, hence they prevent constipation.
But there are adverse effects also. They bind some trace metals resulting in nutritional deficiency.

SECTION – B
(Advanced Writing Skills)

Question.3. You are Vineeta/Vikram, School pupil leader of Rani Laxmi
Bai Senior Secondary School, Gwalior. Draft a notice for your school notice board in not more than 50 words inviting the names of the students who want to participate in the cultural programme organized in aid of the victims of the recent Assam floods.
OR
You have a three bedroom flat in Dwarka, which you want to let out on rent. Draft an advertisement in not more than 50 words to be published in “The Times of India” under classified columns, Contact 2758902.
Answer:

Question.4. Maxim Gorky School, Kodaikanal celebrated “Nutrition Week” from 1st September to 7th September by arranging inter-school cookery contests, oratorical, painting and poster competition, besides talks by eminent nutritionists and medical professionals. There was an overwhelming response from students and parents. Prepare a report in 100¬125 words to be published in your school magazine. You are Arjun/Anita, School pupil leader.
OR
You are Roshan/Rohini, School Pupil Leader of Meerut Public School, Meerut. Your school joined a campaign organized by various agencies of your city to create awareness among people to conserve water. Write a report in 100-125 words highlighting the activities such as rain water harvesting etc.
Answer:
NUTRITION-WEEK
REPORT BY: ANITA (School Pupil Leader)
Maxim Gorky School, Kodaikanal celebrated Nutrition
Week from 1st September to 7th September in the school auditorium. The celebration started with lightning of candles by our respected Principal Sir followed by his inspirational speech on the present day’s health issues and the impket of diet on it. Different schools participated in various competitions organized by the school. The competitions included inter¬school cookery contests, oratorical, painting and poster competition, besides talks by eminent nutritionists and medical professionals was also organized. The students as well as their parents gave an overwhelming response because nowadays everybody is conscious about their health and well-being. The speech on the nutritional value of food by a student, was praised by all. The programme was a combined effort of the teachers and the students and received a huge appreciation by the ones present there.
In the end, the results of the competitions organized were declared and the winners were awarded prizes by Principal Sir.
OR
WATER CONSERVATION
A Report By: Rohini (School Pupil Leader)
Water scarcity today has become a big issue which if not dealt with in time, will turn out to be a hazard.To make people aware to conserve water, Meerut Public School joined a campaign organised by various agencies of the city. People in large numbers attended it and were asked to conserve every drop of water and not waste it unnecessarily. Small skits presenting “* the ways of conserving water were presented by the children.
It was an easy approach as the venue of the campaign was the Public Park and the passers by also stopped to become a part of the campaign. Besides, importance of rain water harvesting and the method to do it was also explained. Without water there is no life. They were encouraged to improve water management practices that reduce the wastage of water and enhance the beneficial uses of water. Some ancient methods of water conservation should also be practiced. In case the water is not used wisely by anyone, then heavy fine should be _ imposed. Public was motivated by this, and they joined hands and took oath to use water properly and motivate others also.

Question.5. Write a letter to your cousin, Raj Prakash who is currently staying in Dubai explaining the process of CCE, being used by CBSE for the secondary school examination in its affiliated schools. Also mention how you and your classmate have reacted to this scheme. You are Narain/Nisha, 20 Fort Road, Mumbai.
OR
Recently you travelled from Bangalore city to Vasco Express. To your dismay, you found that the coach was infested with cockroaches. Write a letter to the editor “The Hindu” drawing the attention of the General Manager, Southern Railways, to the prevailing unhygienic conditions and asking for remedial action. You are Saroj/Saran, 5/31 Bangalore Cantt., Bangalore.
Answer:
20, Fort Road, Mumbai 20th April, 2014
Dear Raj Prakash,
Hope you will be good in your health and very well adjusted in the atmosphere of Dubai. How do you find your school ? What pattern of examination is followed there ? Here, in our schools, CBSE has started a new pattern-CCE (Continuous and Comprehensive Evaluation). This system evaluates the performance of the students in scholastic as well as co-scholastic areas. It has lessened the burden of the children and we feel that it will go a long way. It includes the formative and summative assessment. With this new system it has become possible for us to learn and do-it-yourself in a fun-filled way. Learning has become a pleasure as it has taken away the fear of examination. It not only excel us in academics but our holistic development also. We all are enjoying it and it is a positive approach towards learning.
Hope you will be doing fine in your studies. Convey my regards to uncle and aunty.
Yours affectionately,
Nisha .
OR
5/31, Bangalore Cantt.
Bangalore .
10th January, 2014 The Editor ,
The Hindu ,
Subject: Unhygienic conditions in train coaches Dear Sir,
Through the columns of your esteemed newspaper, I would like to draw the attention of the General Manager, Southern Railways towards the unhygienic conditions of train coaches. „ Recently, I was travelling from Bangalore city to Vasco in Vasco Express, I noticed that the coach was infested with cockroaches. The sheets and blankets given to the passengers were not properly washed; the food was also stale and uncovered, toilets were unclean, wash basins were dirty. For this reason also, the cockroaches are breeding and the whole place is infested with them. Therefore imrtiediate remedial action is required. There should be regular check on the cleanliness of the coaches and the staff members who are given the duty, should also be taken into charge. If they are not performing their duty, they should be fined so that the negligence is not repeated. And to be sure, this will bring a definite change.
I shall be grateful if this letter finds a place in your newspaper.
Yours Sincerely .
Saroj.

Question.6. Write an article in 150-200 words for your school magazine on the topic. “Obesity among School Children.” You are Mohini/Mohit.
OR
You are Rainesh/Ruchika. Write an article in 150-200 words for your school magazine on the topic, “Life without Modern Gadgets”.
Answer:
OBESITY AMONG SCHOOL CHILDREN . By: Mohini
The most common problem found among the children in todays scenario is the growing problem of obesity. This is the result of present day lifestyle where parents are much responsible for it. Even the tastes of the children have changed a lot and they are moving towards junk food like burgers, pizza, pasta and many more. These are not only harmful for their proper growth but also affect their metabolism. As the children are confined to their rooms playing on laptops, computer games and mobiles, the outdoor activities have come to an end. As a result more and more children are becoming obese and overweight which is alarming because it causes health problems which in result, leading to social issues. They are likely to be teased by their peers and they tend to become inactive. Once children become obese; it is very difficult to return to the original shape. Apart from this, the risk factors are very high. They are more prone to high . blood pressure, weak heart, diabetes, orthopedic disorders etc. So the only remedy for this is the awareness, less intake of junk foods, consumption of homemade food, avoiding aerated drinks and more and more physical activities. Then only this problem can be overcome.
OR
LIFE WITHOUT MODERN GADGETS
By: Ruchika
Science has made life easy, convenient, comfortable, better and more beautiful. Its achievements, discoveries and inventions are wonderful. Among them is the boon of gadgets. We cannot think of over life without gadgets as it Would just be miserable. Every device or appliance has a unique purpose. They have revolutionized our life so much that without them we feel handicapped. Beginning from kitchen, gadgets like mixer, microwave oven, refrigerator and water purifier have proved to be a boon. Cell phones are the center of our life. t I-phones and I-pad have huge potential, we can listen to our favorite music while travelling and need not carry heavy radios.
Our life starts with the sound of an alarm clock, so we can say that our day begins with gadgets. They work as our personal assistant. In offices, meetings, trainings and all, we are dependent on them only. Even at the shops, libraries, railways, banks, airports, a computer is required for booking tickets and keeping accounts. If for a day our internet is not working, we feel paralyzed. It feels as something important is missing from our life. Thus, these gadgets have left a remarkable impact on our lives and we cannot work or go without them.

Question.7. Read the extract given below and answer the questions that follow:
The stunted, unlucky heir Of twisted bones, reciting-a father’s gnarled disease, His lesson, from his desk. At the back of the dim class One unnoted, sweet and young.
OR
Driving from my parents Home to Cochin last Friday Morning, I saw my mother, beside me,
Doze, open mouthed, her face ashen like that Of a corpse and realized with pain That she was as old as she looked …
(i) Who is this ‘unlucky heir1 and what has he inherited ?
Answer : The boy who has twisted bones and is sitting in the slum classroom is the unlucky heir. He has inherited the gnarled disease of twisted bones from his father.
(ii) What is the stunted boy reciting ?
Answer : The stunted boy is reciting his father’s gnarled disease and his lessons.
(iii) Who is sitting at the back of the dim class ?
Answer : At the back of the dim class, there is an unnoted, sweet and young dreamer sitting, who is dreaming of squirrel’s game.
(i) Where was the poet driving to ?
Answer : The poet was driving to Cochin from her parents home.
(ii) Why was her mother’s face looking like that of a corpse ?
Answer : Her mother’s face was looking like a corpse because she was old, weak, pale and lifeless.
(iii) What did the poet notice about her mother ?
Answer: The poet noticed that her mother’s mouth was open and her face looked like that of a corpse.

Question.8. Answer any three of the following in 30-40 words each :
(a) What does Keats consider an endless fountain of immortal drink and why does he call its drink immortal ?
Answer : Beauty, according to Keats is immortal and is continuous source of motivation and inspiration and things of beauty are like endless mountains pouring from heaven.
It is an endless fountain of beautiful things so that man can enjoy happiness and peace.
(b) What are the different kinds of wars mentioned in the poem ? What is. Neruda’s attitude towards these wars ?
Answer:The poet talked of the chemical wars, war with fire, wars with ammunition, war with environment and green wars. According to him, these wars are the gate to destruction, therefore should be avoided, as there will be no survivors to enjoy the victory.
(c) What lies heavily on Aunt Jennifer’s hand ? How is it associated with her husband ?
Answer : The wedding band and the ring lie heavily on Aunt Jennifer’s hand. The ring symbolizes the weight of her marriage which she has to bear, dead or alive. It reminds her of the pressures of an unhappy and unpleasant marriage.

Question.9. Answer any three of the following in 30-40 words each:
(a) What was the order from Berlin and what changes did it cause in the school ?
Answer : There was an order from Berlin that French would not be taught in school anymore. Instead German would be taught by a new teacher. That was probably their last French lesson. It was not a Sunday morning yet, there was no noise or activity in the school. The French teacher Mr. Hamel, seemed to be calm and he was becoming emotional. He was wearing a special dress and all the villagers were sitting on the back benches of the class. The whole atmosphere of the school was silent and peaceful.
(b) How did Douglas make sure that he conquered the old terror ?
Answer : The old terror always returned whenever Douglas was alone in the pool. He covered the length of the pool but when he was not satisfied, he went to Lake Wentworth and ^ swam two miles to overcome his terror. The terror was now gone and he laughed at it.
(c) Why was Sophie jealous of Geoff’s silence ?
Answer : Sophie was jealous of Geoff’s silence because she wanted him to share everything as she used to do. Geoff was an introvert and spoke very little. She thought that there was something about his life that was unknown to her.

Question.10. Answer the following in 125-150 words :
OR
Why did Gandhiji agree to a setdement of 25 per cent refund to the farmers ? How did it influence the peasant- landlord relationship in Champaran ?
Answer : Gandhiji agreed to the settlement of 25 percent because the amount was not important for him but to release the peasants from the indigo raising agreement was much more important. The British planters wanted to prolong the agreement but Gandhiji proved to be wiser. He fought for the poor peasants a long battle for one year and managed to get justice for them. This was a moral victory for them. Even the Britishers had to compromise with their pride and prestige. Peasants now got the courage and became aware of their rights. Their money and time was saved and within few years British planters were forced to give up their estates and these were returned to farmers. They became the owners of their own land. It also ignited the feelings of self-dependence and patriotism in farmers.

Question.11. Answer the following in 30-40 words :
Give a character-sketch of the Governor of Oxford Prison based on your understanding of the story ‘Evans Tries an O-level’.
Answer : Governor of Oxford Prison was a generous man who allowed Evans to appear for exam. Evans was a criminal and had escaped from jail twice, so the governor took all the possible precautions for the smooth conduct of examination. The examination had been arranged in the cell itself. The door was locked one day before and the security was made very tight. Everything was checked thoroughly to ensure that there was no way that could help him escape. This shows that he was very wise, on the other hand he was so simple that he couldn’t understand the cunningness of Evans.

Question.12. Answer the following in about 100 words:
There is a saying ‘kindness pays, rudeness never’. In the story ‘The Rattrap’ Edla’s attitude towards men and matters is different from her father’s attitude. How are the values of concern and compassion brought out in the story, ‘The Rattrap’ ?
Answer : Edla, the ironman’s daughter was totally different from her father. In the beginning, the iron master seemed to be very sympathetic when he mistook the’stranger for one of his old acquaintance. He even sent his daughter to call for him when he did not agree to come to their house. But soon his attitude changed when he came to know the truth that the stranger was someone else. He called him dishonest and threatened to hand him over to the police. Whereas his daughter was entirely different from her father. She had different-ways of looking at things. She was affectionate and considerate. She acted more wisely than her father. She stopped her father from behaving badly towards the stranger. She proved to be a good host and it was her, who brought change in his behavior. It was her generosity and sympathy that converted him entirely. These values strengthen our hope in goodness.

Question.13. Answer the following in 30-40 words :
(a) What forced Dr. Sadao to be impatient and irritable with his patient ?
Answer : When Dr. Sadao saw the difficulties faced by his wife in the absence of maids and servants due to the presence of an enemy in his house, he felt impatient and irritable with him. Besides when this secret was out that he was sheltering an enemy, he feared of getting into serious trouble. It caused a great deal of tension to him.
(b) Why does Jo insist that her father should tell her the story with a different ending ?
Answer : Jo insists that her father should tell her the story with a different ending because-she wants that other animals should play with Roger Skunk and for that he must smell like roses. According to her, the mother is wrong as she made him smell foul again and the wizard should hit his mother. In fact, she wants to assert her views on her father.
(c) If you were to give a different ending to the story ‘On the face of it’ how would you end it ?
Answer : If I, were given a chance to end the story, surely it would be a happy ending. Mr. Lamb would not have died and Derry along with him would have started a new life. They would have been living happily in each other s company.
(d) What were the articles in the stalls and shops that fascinated Bama on her way back from school ?
Answer : It was a daily routine of the writer to walk home from school, which was a ten minute walk. But it always took her thirty minutes to reach home as the stalls and shops on the way fascinated Bama alot. These stalls and shops were of sweets, dried fish, fried snacks etc.

CBSE Class 10 Science Practical Skills – Image Formation by a Convex Lens

BASIC BUILDING CONCEPTS
Students are advised to go through the basic concept of experiment no. 4(b) before going through this.
Image
An optically representative reproduction of an object, formed by a lens or mirror due to the phenomenon of reflection or refraction is called the image of an object.

Types of Image:

1. Real image and
2. Virtual image

Real Image

• It is formed by the light rays after reflection or refraction when they
  • actually meet or intersect with each other, or
  • actually converge at a point.
• It can be obtained on the screen.
• It is always inverted, i.e. upside down with respect to the object.
• The size of the real image depends on the position of the object. So, it can be diminished, or of same size as that of the object or enlarged.
• It is formed by both convex lens and concave mirror.

Virtual Image

• It is formed by the light rays after reflection or refraction when they
  • appear to diverge from a point, or
  • appear to meet when they are produced in the backward direction, or
  • intersect apparently.
• It cannot be trapped on the screen.
• It is always erect, i.e. upside up with respect to the object.
• It is formed by both concave and convex lens. It is also formed by concave, convex and plane mirrors.

New Cartesian Sign Convention
By using New Cartesian Sign Convention, one can study the formation of images by convex lens as well as concave lens also.

You can also download NCERT Class 10 Science to help you to revise complete syllabus and score more marks in your examinations.

To understand the image formation by a convex lens, we consider the convex lens as a thin lens having a small aperture which is much less than its radius of curvature. Let its optical centre be considered as origin and its principal axis as the x-axis of the co-ordinate system.
In order to draw ray diagram for the lenses, following rules will be taken into consideration:

1. The object is always kept on the left of the lens, i.e. the light from the object is incident on the lens from the left hand side of the lens.
2. All the distances parallel to the principal axis will be measured from the optical centre of the lens.
3. All the distances are measured along the positive x-axis, (i.e. in the direction of incident ray) will be taken as positive.
4. All the distances are measured along the negative x-axis (i.e. in the direction opposite to that of incident ray) will be taken as negative.
5. All the distances measured above the principal axis (i.e. along the positive y-axis) will be taken as positive.
6. All the distances measured below the principal axis (i.e. along the negative y-axis) will be taken as negative.

The New Sign Convention for the convex lens can be illustrated as follows:

Image Formation by a Convex Lens
With the help of the mentioned sign conventions, one can locate the image of the object formed by a convex lens.
The following points must be considered for drawing the ray diagrams:

1. A ray of light from the object placed on the principal axis on the left hand side of the lens, parallel to the principal axis, will pass through the principal focus F₂ after refraction through the lens as shown in figure (a).
2. A ray of light passing through the first principal focus Fx will emerge parallel to the principal axis after refraction from a convex lens as shown in the figure (b).
3. A ray of light passing through the optical centre ‘O’ of the lens, emerges undeviated, i.e. it does not suffer any deviation from its path after refraction as shown in the figure (c).
   
   Using any of the two given rules and New Cartesian Sign Convention, neat ray diagrams can be drawn for the various positions of the object in front of a convex lens in order to locate the position of the image, its nature and the size.

Magnification Produced by a Lens
It is the ratio of the size of image (h₂) to the size of object (h₁). It is represented by ‘m’
m = Size of image(A’B’) / Size of the object (AB) = h₂ / h₁
According to the New Cartesian Sign Convention,

• it is negative when real image is formed by a convex lens.
• it is positive when virtual image is formed by a convex or concave lens.

EXPERIMENT – (a)

AIM
To find the image distance for varying object distances in case of a convex lens and draw corresponding ray diagrams to show the nature of image formed.

MATERIALS REQUIRED
A thin convex lens, a lens holder fitted in a stand with centered mark, a piece of a semi-transparent sheet act as screen fixed to a stand with centered mark, a small candle and a stand for candle with centered mark and a meter scale (or a ruler)

THEORY
The position, nature and size of the image of an object formed by a thin convex lens depends on the position of the object with respect to its optical centre and can be studied by using New Cartesian Sign Convention and drawing the corresponding ray diagrams.
A real, inverted image of an object can be focussed on a screen placed on the other side of the convex lens if the object is placed beyond the focus of the convex lens as shown below.

The nature, position and size of the image can be noted and measured from the optical centre of the convex lens.

PROCEDURE

1. Fix a thin convex lens on a lens holder and place it vertically on the table.
2. Place the semi-transparent paper screen in a vertical position fitted to a stand on the right hand side of the convex lens.
3. Mount the candle in a centered mark stand.
4. Set-up the arrangement as shown above.
5. Place the lighted candle stand at a distance far off (or infinite distance) beyond 2F1 vertically in front of a thin convex lens. Adjust the height of the centre of convex lens nearly equal to the height of the flame of the candle as shown below.
   
   Here the flame is considered as the object AB. Measure and record the height h of the candle flame when the flame does not flicker.
6. Obtain the sharp, real image of the candle flame on the screen by moving it in the forward or backward direction. With the help of measuring scale, record the position of lens L and screen S in the observation table. The difference between these two readings (the centre of the convex lens and centre of the screen) gives the approximate focal length of the convex lens.
7. Now shift the lighted candle nearby but beyond twice the approximate focal length (2F) of the thin convex lens.
8. Adjust the position of the screen by moving it away from the previous position to get a sharp and real image A’B’ of the candle flame AB on it. Note and record the position of the lighted candle AB, screen s and lens l. Also measure and record the height h’ of the image of the flame of the lighted candle obtained on the screen.
9. Repeat the experiment by placing the lighted candle in front of the convex lens LL’ at a distance
   • equal to 2F
   • less than 2F but more than F.
10. Locate the position of screen in each case by moving it still further away from lens to get the real and sharp image of the flame and record your observations for the position and height of image in the observation table in each case.
11. Now keep the lighted candle at F and try to locate the image on the screen by moving it gradually away from the lens. You may not be able to obtain the image because when the object is at F, the image will be formed at infinity and is blurred due to high magnification.
12. Find the distance between the optical centre of the lens and candle flame (object) x (say) and corresponding image distance between the optical centre O of the lens and the screen, y (say).
13. Repeat the experiment three more times by varying x by changing the position of the lens. Locate the sharp image of the flame and record the position and height of the image in each case.
14. With the help of data obtained, draw the corresponding ray diagrams in each case to show the nature of image formed.

OBSERVATIONS AND CALCULATIONS
Approximate focal length of the thin convex lens, F = …………. cm
Height of the candle flame, h = ………….. cm.

RESULT

1. As the object is moved from infinity towards the optical centre of the convex lens,
   • the image distance increases gradually and
   • size of image also increases gradually.
2. When the object is at infinite distance, the image formed by the convex lens is real, inverted and sharp but diminished in size at the focus is obtained. This gives the approximate focal length of the convex lens. The corresponding ray diagram is shown below.
   
3. When the position of object is beyond 2F₁, the image formed is real, inverted, and smaller in size and lies in between F₂ and 2F₂. The corresponding ray diagram is shown in figure (b) in experiment 1(b).
4. When the position of object is at 2F₁, the image formed is real, inverted, same size as the size of object and lies at 2F₂. The corresponding ray diagram is shown in figure (c) in experiment 1(b).
5. When the position of object lies between F₁ and 2F₁ the image formed is beyond 2F₂. It is real, inverted and enlarged or magnified. The corresponding ray diagram is shown in figure (d) in experiment 1(b ).
6. When the position of object lies at F₁, the image formed is at infinity, It is real, inverted and highly enlarged. The corresponding ray diagram is shown in figure (e) in experiment 1(b).

PRECAUTIONS

1. The convex lens should be thin and having a small aperture and should be without any scratches to get the distinct image of the lighted candle.
2. The centre of the lens, the tip of the candle flame and the centre of the screen should lie in the same straight line and parallel to the measuring scale.
3. The base of the candle stand, convex lens and screen should be parallel to the measuring scale.
4. All distance should be measured between the centred mark of each stand.
5. The focal length of the thin convex lens must preferably be between 15 to 20 cm.
6. The convex lens should be kept in such a way that the light rays coming from the lighted candle always falls on its aperture without any obstruction.
7. Flame must be uniform throughout the experiment. To avoid its flickering, switch off the fan and perform the experiment in calm air. Otherwise you can use the long filament bulb instead of burning candle if the tip of its flame is not found to be stable.
8. It is better to perform this experiment in a dark room or in shade where no direct light reaches to the working table to get the sharp and distinct images of the candle flame.
   Note: It is advisable for the students that after doing the candle screen experiment for measuring the image distance, they must perform the following activity to understand how to draw the images of an object formed by a convex lens for the various positions of object.

EXPERIMENT – (b)

AIM
To draw the images of an object formed by a convex lens when placed at various positions.

MATERIALS REQUIRED
A drawing board, sheets of white paper, measuring scale, protractor and drawing pins or adhesive tape.

THEORY
The New Cartesian Sign Convention and image formation rules for the convex lens help us to draw ray
diagrams forming images by a convex lens for various positions of the object.
The position of the object may be

• at infinity,
• beyond 2F₁
• at 2F₁,
• between F1 and 2F₁
• at F₁
• between focus (F₁) and optical centre (O) of the convex lens.

For the sake of convenience and clarity of the ray diagram, two rays are considered. The intersection of two refracted rays gives the position of the image formed by the lens.

PROCEDURE

1. Fix a white sheet of paper on a drawing board with the help of drawing pins.
2. Draw a thin line 12-15 cm in length in the middle of the paper. Name it as XX’.
3. Mark point ‘O’ at the centre of the line. Draw a perpendicular line of equal height at the point O above and below XX’. Name it L₁L₂.
4. Make a thin convex lens of small aperture around L₁L₂. Assume O as optical centre of the lens.
5. Mark points F₁ and F₂ on the line XX’ on either side of the lens L₁L₂ such that OF₁ = OF₂ where F₁ and F₂ are the two principal foci of the lens.
6. Also mark points 2F₁ and 2F₂ on the line XX’ such that O(2F₁) = 2(OF₁) and O(2F₂) = 2(OF₂).
   OBJECT AT INFINITY
7. Draw an object AB of suitable height ‘h{ at a very far distance from the lens considered to be placed at infinity.
8. Draw the lines parallel to the principal axis such as CD, GH, PQ and RS incident on the surface of convex lens.
9. Draw the refracted emergent rays on the other side of the lens such as DF₂, HF₂, QF₂ and SF₂ through the convex lens and intersect at the principal focus F₂. A diminished image of the distant object is formed at F₂. It is real and inverted.
   
10. Record the result in an observation table.
    OBJECT BEYOND 2F₁
11. Fix another white sheet of paper on the drawing board.
12. Repeat the steps (2) to (6).
13. Draw an object AB of suitable height ‘h₁‘ beyond 2F₁ as shown.
14. Draw a ray AE parallel to the principal axis F₁OF₂ incident on the surface of convex lens at point E.
15. Draw another ray AO through the optical centre O of a convex lens and extend it to other side of the lens as OA’.
16. On the other side of a lens, draw the ray EF₂ passing through the focus F₂ and interszecting the ray OA’ at A’ as shown in the figure, forming an image B’A’.
    
17. Measure the height of the object AB(h₁) and height of the image A’B'(h₂).
18. We observe from the figure that the image formed is real, inverted, smaller in size and in between F₂ and 2F₂.
19. Record these observations in the observation table.
    FOR OTHER POSITIONS OF THE OBJECT
20. Repeat the above steps similar to the previous case. Draw neat ray diagrams for other positions of the object as shown in the,
    Figure (c) at 2F₁.
    Figure (d) between F1 and 2F₁.
    Figure (e) at focus F₁.
    Figure (f) is in between focus F₁ and optical centre O of the convex leris.
    
21. Measure the height of the object AB(h₁) and height of image A’B'(h₂) respective in all cases (c) to (f) as listed in step 20. Record them in the observation table.
22. Note down the nature, relative size and position of the image formed by the convex lens for the various positions of the object.
23. Tabulate your observations in the observation table.

OBSERVATION AND CALCULATION

RESULT
The characteristics of image formed by a convex lens for various positions of the object is summarised in the observation table.

PRECAUTIONS

1. Use very sharp tipped pencil to draw thin lines in various ray diagrams.
2. The convex lens drawn should be thin and of small aperture for obtaining the distinct image.
3. Protractor should be used to draw the convex lens.
4. All uprights should be vertical.
5. The aperture of the lens in all figures should be same.
6. Proper arrows should be drawn to indicate the incident and the refracted rays.

INTERACTIVE SESSION

Question 1.
What is double convex lens?
Answer:
A lens which has two refracting spherical surfaces, bulging outwards is called a double convex lens or simply convex lens.

Question 2.
What is the function of a convex lens?
Answer:
It can converge the incident light rays.

Question 3.
Which law is obeyed by the light rays when refracted through a convex lens?
Answer:
Laws of refraction.

Question 4.
Name the point on the principal axis of a convex lens where the ray of light passing through it does not suffer any deviation.
Answer:
Optical centre ‘O’ of the lens.

Question 5.
What happens to the size of image when the object is moved from infinity towards the optical centre of the lens?
Answer:
The size of the image increases gradually.

Question 6.
What would be the nature of image when the object lies in between infinity and F?
Answer:
Real and inverted

Question 7.
Suppose you move the candle from the focus of a convex lens towards infinity. In which direction should the screen be moved to get the real and sharp image?
Answer:
Screen must be shift towards the lens.

Question 8.
What happens when the experiment is performed with scratches on the lens?
Answer:
Sharp and distinct image cannot be obtained accurately.

Question 9.
The image of a candle formed by a convex lens is obtained on a screen. Will the full size of image be obtained if the lower half of the lens is covered with black paper and made completely opaque ?
Answer:
Yes, the full size image with less brightness will be obtained by the another half portion of the convex lens.

Question 10.
According to the New Cartesian Sign Convention, what is the nature of a focal length of a convex lens?
Answer:
Positive.

Question 11.
Is virtual image erect or inverted?
Answer:
Erect and enlarged.

Question 12.
Where should an object be placed in order to use a convex lens as a magnifying glass?
Answer:
Between focus and optical centre of the lens.

Question 13.
On what factor does the size of an image formed by a lens depend?
Answer:
It depends on the position of an object from the lens.

Question 14.
Why do you consider only two rays to draw the ray diagram?
Answer:

• For the sake of clarity of ray diagram.
• To know their directions easily after refraction from the lens.

Question 15.
Why do you draw the equiconvex lens?
Answer:
If the drawn lens is not equiconvex, then the condition OF₁ = OF₂ will not hold good.

Question 16.
According to the New Cartesian Sign Convention, what will be the sign of image distance when it is formed beyond 2F₂?
Answer:
Positive.

Question 17.
Which of the following quantities remains the same when light goes from one medium to another medium?

• speed
• frequency
• wavelength
• intensity Examinee

Answer:
Frequency.

NCERT LAB MANUAL QUESTIONS

Question 1.
What is the nature of an image formed by a thin convex lens for a distant object? What change do you expect if the lenses were rather thick?
Answer:
Nature of image formed by a thin convex lens for a distant object is real, inverted and highly diminished. It is formed at the focus of a convex lens. Thick convex lens has shorter focal length so image distance will be reduced as compared to thin lens.

Question 2.
You are provided with two convex lenses of same aperture and different thickness. Which one of them will be of shorter focal length?
Answer:
Thick convex lens will have shorter focal length than that of thin convex lens.

Question 3.
How will you distinguish between a convex lens and a concave lens by holding in hand and looking the printed page through them?
Answer:
If the letters of printed page appears enlarged then it is a convex lens, but if they appear diminished then it js concave lens.

Question 4.
A distinct image of the lighted candle has been obtained on screen with fixed position using a thin convex lens. Why does the image of the candle get blurred if the position of any one of them is slightly disturbed?
Answer:
The image of lighted candle get blurred due to change in candle position or lens position while keeping position of screen be fixed, the rays may meet before or after the screen.

Question 5.
Why do we require a calm atmosphere to perform this experiment?
Answer:
With the flickering flame, we cannot measure its height as well as its image height. Also, it would be difficult to get the sharp image other than calm atmospheric conditions.

Question 6.
Why is it preferred to perform this experiment in dark or in shade?
Answer:
To get the sharp and distinct image of the candle flame, it should be better to perform this experiment in dark or in shade.

Question 7.
Sometimes, the image formed by a convex lens of an object placed at 2F₁ is not of the same size and at location 2F₂ on the other side of the convex lens. What could be the possible reason(s) for such a situation?
Answer:
The image formed by a convex lens, when the object is placed at 2F₁ is of the same size and is located at 2F₂ on the other side of convex lens is true only when the convex lens is thin and having a small aperture. If the lens is thick and having a larger aperture, then there are certain defects in the image formed.

Question 8.
A ray of light is passing through the principal focus of a convex lens. How will it emerge after refraction through the lens?
Answer:
It will emerge parallel to the principal axis after refraction through the convex lens because it is measured against the direction of incident ray of light.

Question 9.
An object is placed on the left side of a lens (having 10 cm focal length) at a distance of 20 cm. What will be the sign of object distance?
Answer:
According to the New Cartesian Sign Convention, the sign of object distance is negative because it is measured against the direction of incident ray of light.

PRACTICAL BASED QUESTIONS
Multiple Choice Questions/VSA (1 mark)

Question 1.
Study the diagram given below:

The diagram showing the correct path of the ray after refraction from the convex lens is

Question 2.
A student suggested the following guidelines to his friend for performing the experiment to draw the images of an object formed by a convex lens, when placed at various positions:
(i) A ray of light from the object, parallel to the principal axis, after refraction from a convex j lens will pass through the principal focus on the other side of the lens.
(ii) A ray of light passing through the principal focus will emerge parallel to the principal axis.
(iii) A ray of light passing through the optical centre of a lens will emerge without any deviation from the lens.
(iv) The convex lens drawn should be thick and of large aperture to obtain the clarity of ray diagram.
When he showed these guidelines to his teacher, the teacher corrected and modified one of the following guidelines:
(a) (i)
(b) (ii)
(c) (iii)
(d) (iv)

Question 3.
To draw the images of an object formed by a convex lens for its various positions, a student summarised the New Cartesian Sign Convention as given
(A) Light rays from the object falls on the lens from the left hand side.
(B) All measurements should be taken from the first principal focus of the lens.
(C) All measurements taken to the right side of optical centre are taken as positive.
(D) Distance measured from the optical centre to left side are taken as negative.
Which of the above statements in his summarisation is incorrect?
(a) A
(b) B
(c) C
(d) D

Question 4.
Identify the correct ray diagram drawn by a student

Question 5.
For making the ray diagrams for a convex lens, a student must consider at least two refracted rays to locate the position of image. Out of the three rays shown by him, the incorrect one is

(a) I
(b) II
(c) III
(d) I and II both

Question 6.
In order to find the image distance for varying object distance in case of convex lens, a student was asked to measure the image distance on getting the sharp image of the lighted candle placed in front of the convex lens at twice of its focal length, she should measure the distance between
(a) lens and lighted candle.
(b) tip of the lighted candle and centre of the screen.
(c) centre of lens and centre of the screen.
(d) centre of a lens and vertex of a screen.

Question 7.
The candle screen experiment gives only the quantitative idea for recording the position of lighted candle, convex lens and the screen. This is due to
(a) the height of wax candle had decreased since it was burning for long time.
(b) the readings were more or less correct but were not precise.
(c) it is not possible to place the screen exactly at the actual meeting point of the refracted rays.
(d) all of the above .

Question 8.
Study the following diagrams: [AI 2013]

The diagrams showing correct path of the ray after refraction from the convex lens are
(a) I, II and III
(b) II, III and IV
(c) III, IV and I
(d) I, II and IV

Question 9.
Study the following ray diagrams drawn by four students to locate the position of the image formed by a convex lens when the object is placed at 2F:

The correct ray diagram is that of student
(a) I
(b) II
(c) III
(d) IV

Question 10.
Given below are two lenses: [CBSE 2013]

Teacher asked her students to draw for both the lenses, image formation for an object placed at infinity. Image distance for the two
(a) would be larger for A than for B
(b) would be smaller for A than for B
(c) would be equal for both
(d) cannot be predicted without performing experiment

Question 11.
In the diagram given below, an object is placed in front of a convex lens. The image thus formed will be [CBSE 2013]
(a) always real
(b) always erect
(c) may be real or virtual depending on its position with respect to focus

(d) always virtual

Question 12.
Out of the five incident rays s find the three rays that are of refraction and may be used for locating the position of image formed by a convex lens [Delhi 2013]

(a) 1, 2 and 3
(b) 2, 3 and 4
(c) 3, 4 and 5
(d) 1, 2 and 4

Question 13.
Observe the figures given below for three lenses A, B, and C

Converging power of the three lenses will be respectively as
(a) A > B > C
(b) B > A > C
(c) B > C > A
(d) C > B > A

Question 14.
A student draws a ray diagram for image formation by a convex lens for object placed at 2F. According to him, the magnification produced by convex lens in this case is [CBSE 2013]
(a) +1
(b) + 2
(c) +3
(d) – 1

Question 15.
A student was asked to draw a diagram for image formation of an object placed at a distance of 4 cm from a convex lens of focal length 5 cm. After completing the diagram, he would note that the nature of image formed is [CBSE 2013]
(a) real, inverted and magnified
(b) virtual, erect and magnified
(c) virtual, inverted and magnified
(d) virtual, erect and diminished

ANSWER KEY

1. (b)
2. (d)
3. (b)
4. (d)
5. (c)
6. (c)
7. (d)
8. (d)
9. (b)
10. (a)
11. (c)
12. (b)
13. (c)
14. (a)
15. (b)

Short Answer Questions (2 Marks)

Question 1.
To construct a ray diagram, we use two light rays which are so chosen that it is easy to know their directions after refraction from the convex lens. List these two rays and state the path of these rays after refraction.
Answer:
Two rays chosen for refraction are:

• A ray of light parallel to the principal axis.
• A ray of light passing through optical centre of a lens.

Path of these rays after refraction:

• A ray parallel to the principal axis, after refraction through the lens, will pass through the principal focus on the other side of the lens.
• A ray of light passing through optical centre of a lens will emerge from the lens without any deviation in its path.

Question 2.
A student focused the image of a candle flame on a white screen by placing the flame at various distances from a convex lens. He noted his observations as given below:

In which case

1. is the size of image smaller than the size of object?
2. is the size of object and image same?

Give reason for your answer.

Answer:

1. When the object is placed between infinity and 2F, diminished, real and inverted image is formed. So in the first observation, size of the image is smaller than the size of object.
2. When the object is placed at 2F, an image of the same size as that of the object is formed at 2F on the other side of the lens. It is real and inverted as well. Hence in 3rd observation, the size of object and image is same.

Question 3.
Draw ray diagrams to represent the nature, position and relative size of the image formed by a convex lens for the object placed:

1. at 2F.
2. between F and the optical centre O of the lens.

Answer:

1. When the object is at 2F
   
   Nature of image: Real and inverted.
   Size of image: Same as that of object. Position of image: At 2F on the other side of the lens.
2. When the object is in between F and the optical centre 0 of the lens:
   
   Nature of image: Erect and virtual,
   Size of image: Enlarged.
   Position of image: On the same side of the lens.

Question 4.
A lighted candle, placed on a metre scale at 8 cm mark, was focused on a white screen placed at 92 cm mark, using a converging lens placed on the scale at 50 cm mark. With the help of this data, he finds that focal length of the given converging lens is 21 cm.

1. Find the position of image formed if the object is shifted towards the lens at a position of 29 cm.
2. State the nature of image formed if the object is further shifted towards the lens.

Answer:

1. As object is shifted towards the lens at a position of 29 cm, new object distance is, u’ = – (50 – 29) = – 21 cm. This means that object is now placed at the focus of the convex lens. If the object is placed at the focus of a convex lens, final image will be formed at infinity as the rays coming from the focus of a convex lens emerges parallel to the principal axis.
2. If the object is further shifted towards the lens, object is now within the focus of a convex lens, the nature of image formed is
   • virtual, erect, and
   • enlarged or magnified, i.e. larger than the size of object.

Question 5.
It is desired to obtain the erect image of an object, using a convex lens of focal length 20 cm.

1. What should be range of object distance from the lens?
2. Will the image formed be bigger or smaller?

Answer:

1. To get the virtual and erect image formed by a convex lens, object should be kept between optical centre and focus. Therefore, range of the object distance is from 0 to 20 cm.
2. Enlarged and erect image is formed.

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