Lost Notice Writing For Class 7

Lost Notice Writing For Class 7 Format, Examples, Topics, Exercises

Lost Notice Writing For Class 7 Format, Examples, Topics, Exercises

Notice writing is an important aspect of English language learning for students of all ages. In class 7, students are expected to learn the basic format of writing notices, and also develop an understanding of the different types of notices that are used in various contexts. This article will provide you with a comprehensive guide to writing notices for class 7, including examples, topics, and exercises.

Format Of Lost Notice Writing For Class 7:

A notice is a written or printed announcement or piece of information that is meant to be publicly displayed or distributed. The basic format of a notice includes the following elements:

1. Heading: The heading of a notice should be in bold letters and should clearly indicate the purpose of the notice.
2. Date: The date on which the notice is being issued should be mentioned in the top right corner of the notice.
3. Salutation: The salutation or greeting is usually ‘Dear all’ or ‘Attention all’.
4. Content: The content of the notice should be brief, clear, and to the point. It should include all the necessary details such as the purpose of the notice, date and time, venue, contact information, etc.
5. Signature: The notice should be signed by the person or authority issuing the notice.

Also Read: Notice Writing For Class 8

Examples Of Lost Notice Writing For Class 7:

Here are some examples of notices that may be relevant for class 7 students:

1. Notice for an excursion: “Attention all students of class 7! An excursion has been planned for Saturday, 5th May. We will be visiting the local museum and botanical garden. Please bring your permission slips and Rs. 100 for the entry fee. The bus will leave the school premises at 8:30 am sharp.”
2. Notice for a school event: “Dear all, the annual sports day event will be held on Friday, 11th May. The event will start at 9:00 am sharp and all students are expected to participate. Please wear your school uniform and bring your sports equipment. Refreshments will be provided. For further information, please contact the school office.”
3. Notice for a school closure: “Attention all parents and students, please note that the school will remain closed on Monday, 14th May due to maintenance work. We apologize for the inconvenience caused and request you to plan your schedule accordingly.”
4. Notice for a school project: “Dear all, as part of our environmental awareness campaign, we are launching a school project to create a ‘green wall’. All students of class 7 are requested to bring a plant sapling to school on Monday, 28th May. The saplings will be planted in the designated area of the school compound. Please contact your class teacher for further details.”
5. Notice for a school competition: “Attention all students of class 7, a debate competition will be held on Friday, 18th May. The topic for the competition is ‘Should plastic bags be banned?’ Interested students may register their names with their class teacher by Tuesday, 15th May. The competition will start at 10:00 am and prizes will be awarded to the winners.”

Examples Of Lost Notice Writing For Class 7

Topics For Lost Notice Writing For Class 7:

Here are some topics for notice writing exercises that can be given to class 7 students:

1. Notice for a parent-teacher meeting.
2. Notice for a school assembly.
3. Notice for a farewell party.
4. Notice for a cleanliness drive.
5. Notice for a field trip.
6. Notice for a science fair.
7. Notice for a book fair.
8. Notice for a cultural festival.
9. Notice for a health camp.
10. Notice for a scholarship program.

Exercises For Lost Notice Writing For Class 7:

Here are some exercises that can help class 7 students practice writing notices:

1. Write a notice inviting students to participate in a school quiz competition. Include details such as the date, time, venue, and prizes.
2. Write a notice announcing the cancellation of a school event due to unforeseen circumstances. Include details such as the reason for cancellation, the new date if applicable, and any other relevant information.
3. Write a notice inviting parents for a parent-teacher meeting. Include details such as the date, time, and venue, and also mention the purpose of the meeting.
4. Write a notice announcing the results of a school competition. Include details such as the names of the winners, their prizes, and any other relevant information.
5. Write a notice inviting students to participate in a school drama competition. Include details such as the date, time, venue, and rules and regulations.
6. Write a notice announcing a change in the school timings due to extreme weather conditions. Include details such as the new timings, the reason for the change, and any other relevant information.
7. Write a notice inviting students to participate in a school talent show. Include details such as the date, time, venue, and categories for participation.
8. Write a notice announcing the launch of a new school magazine. Include details such as the theme of the magazine, the deadline for submissions, and any other relevant information.
9. Write a notice inviting students to join a school club or society. Include details such as the objectives of the club, the activities that will be conducted, and the benefits of joining.
10. Write a notice announcing the closure of the school due to a public holiday or unforeseen circumstances. Include details such as the date of closure, the reason for closure, and any other relevant information.

Conclusion On Lost Notice Writing For Class 7:

Notice writing is an important skill that class 7 students should develop. It not only helps them to communicate important information effectively but also enhances their overall language proficiency. By following the basic format of notice writing, students can write clear, concise, and effective notices for various purposes. With practice and guidance, students can master this skill and use it to their advantage in their academic and personal lives.

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Report Writing On Road Accident For Class 11 Format, Examples, Topics, Exercises

Report Writing On Road Accident For Class 11 Format, Examples, Topics, Exercises

Report Writing On Road Accident For Class 11 Format, Examples, Topics, Exercises

Introduction:

Road accidents have become a common phenomenon in today’s world. Every day, hundreds of people lose their lives or are seriously injured in road accidents. These accidents not only cause physical harm but also affect the mental and emotional well-being of the victims and their families. In this report, we will discuss road accidents, their causes, consequences, and preventive measures that can be taken to reduce their occurrence.

Also Read: Report Writing On Road Accident For Class 10 

Section 1: Definition of road accidents

A road accident can be defined as an incident that occurs on a road or highway that involves a collision between one or more vehicles, pedestrians, or animals. These accidents can be caused by various factors, including human error, mechanical failure, poor road conditions, or weather.

Section 2: Causes of road accidents

Human error is the most common cause of road accidents. This can include driving under the influence of alcohol or drugs, speeding, reckless driving, distracted driving, and fatigue. Mechanical failure can also cause accidents, such as brake failure or tire blowouts. Poor road conditions, such as potholes or inadequate lighting, can also contribute to accidents.

Section 3: Consequences of road accidents

The consequences of road accidents can be severe and long-lasting. They can result in physical injuries, emotional trauma, and financial losses. In some cases, they can even lead to death. Victims of road accidents may suffer from disabilities or require long-term medical care. Families of victims may also suffer from emotional trauma and financial burdens.

Section 4: Preventive measures

To reduce the occurrence of road accidents, various preventive measures can be taken. These include:

  • Enforcing traffic laws and regulations
  • Educating drivers on safe driving practices
  • Providing adequate infrastructure, such as road signage and lighting
  • Encouraging the use of seat belts and child safety seats
  • Improving vehicle safety features
  • Increasing public awareness campaigns on road safety

Examples Of Report Writing On Road Accident For Class 11:

Example 1:

A road accident occurred on the highway yesterday evening when a car collided with a truck. The car driver lost control of the vehicle, and it collided with the truck, causing severe damage to both vehicles. The car driver was immediately taken to the hospital and is currently receiving medical treatment for the injuries sustained in the accident. The police are investigating the cause of the accident and have appealed to witnesses to come forward with any information they may have.

Example 2:

A pedestrian was hit by a speeding car while crossing the road yesterday afternoon. The pedestrian suffered severe injuries and was rushed to the hospital for treatment. The driver of the car fled the scene after the accident, but the police were able to apprehend them later. It was found that the driver was under the influence of alcohol and was driving without a license. They have been arrested and charged with reckless driving and hit and run.

Examples Of Report Writing On Road Accident For Class 11

Topics For Report Writing On Road Accident For Class 11:

1. The impact of road accidents on society
2. The role of technology in preventing road accidents
3. Road safety education and awareness campaigns
4. The importance of driver behavior in preventing road accidents
5. The impact of weather conditions on road safety

Exercises For Report Writing On Road Accident For Class 11:

1. Write a short paragraph describing a road accident that you witnessed or heard about.
2. Conduct research on road accidents in your country and write a report on the most common causes and preventive measures.
3. Develop a road safety campaign targeting young drivers and present it to your class.
4. Write an essay discussing the impact of road accidents on the economy.
5. Conduct a survey among your peers on their driving habits and attitudes towards road safety, and present the findings in a report.

Format Of Report Writing On Road Accident For Class 11:

Report writing follows a specific format that includes:

1. Title: The title should be brief and informative, and it should give the reader an idea of what the report is about.
2. Introduction: The introduction should provide background information on the topic and outline the main points that will be covered in the report.
3. Body: The body of the report should be divided into sections or subheadings that address the main points of the report. Each section should be clear, concise, and well-organized, and it should include relevant information, facts, and data.
4. Conclusion: The conclusion should summarize the main points of the report and provide recommendations or solutions to the problem or issue discussed in the report.
5. References: Any sources used in the report should be cited in a reference section at the end of the report.

Conclusion On Report Writing On Road Accident For Class 11

Road accidents are a serious problem that affects individuals and society as a whole. By understanding the causes and consequences of road accidents and implementing preventive measures, we can reduce the occurrence of these accidents and make our roads safer. Report writing is an important skill that students can develop to communicate their ideas effectively and contribute to creating a safer environment for everyone on the road.

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CBSE Class 9 Maths Lab Manual – Comparison of Diagonals in Different Quadrilaterals

CBSE Class 9 Maths Lab Manual – Comparison of Diagonals in Different Quadrilaterals

Objective
To explore the similarities and differences between the different quadrilaterals like parallelogram, rectangle, rhombus and square with respect to their diagonals.

Prerequisite Knowledge
Properties of parallelogram, rectangle, square, rhombus.

  1. In parallelogram, diagonals are not equal.
  2. In rectangle, diagonals are equal.
  3. In rhombus, diagonals are not equal but bisect each other at 90°
  4. In square, diagonals are equal and bisect each other at 90°.

Materials Required
Glazed papers, ruler, a pair of scissors, pencil, tracing paper.

Procedure
Case I:

  1. Make a parallelogram on a glazed paper by paper folding and name it as ABCD. Join AC and BD.
  2. Draw and cut replicas of AABC and ABCD. Coincide the diagonals AC and BD.
    CBSE Class 9 Maths Lab Manual – Comparison of Diagonals in Different Quadrilaterals 1
    CBSE Class 9 Maths Lab Manual – Comparison of Diagonals in Different Quadrilaterals 2
    Observation:
    We observe that diagonal AC ≠ diagonal BD.

Case II

  1. Make a rectangle by paper folding on a glazed paper. Name it as PQRS. Join PR and QS.
  2. Cut replicas of ∆PQS and ∆PQR and name them as ∆BCA and ∆EFD.
    CBSE Class 9 Maths Lab Manual – Comparison of Diagonals in Different Quadrilaterals 3
    3. Place two replicas such that AC and ED coincise eachother and side AB is opposite to side FD.
    CBSE Class 9 Maths Lab Manual – Comparison of Diagonals in Different Quadrilaterals 4
    Observation:
    Here we notice that AC = DE. (as they overlap each other)
    ∴ diagonal AC = diagonal DE
    ∴ QS = PR

Case III:

  1. Make a rhombus by paper folding on a glazed paper. Name it as ABCD. Join AC and BD.
  2. Draw and cut replicas of ∆ABC and ∆DCB and name them as ∆PQR and ∆MNO’ respectively.
    CBSE Class 9 Maths Lab Manual – Comparison of Diagonals in Different Quadrilaterals 5
    CBSE Class 9 Maths Lab Manual – Comparison of Diagonals in Different Quadrilaterals 6
  3. Place two replicas such that PR and MO’ coincide each other.
    CBSE Class 9 Maths Lab Manual – Comparison of Diagonals in Different Quadrilaterals 7
    Observation:
    We observe thatPR ≠ O’M.
    ∴ diagonal AC ≠ diagonal BD
  4. Draw and cut replicas of ∆AOB and ∆BOC and verify the congruency of two triangles by placing one over other.
    CBSE Class 9 Maths Lab Manual – Comparison of Diagonals in Different Quadrilaterals 8
    Here BC = AB
    OB = BO
    OC = OA
    ∴∆BOC = ∆BOA
    ∴∠BOC = ∠BOA
    ∴∠BOC + ∠BOA = 180° (linear pair angles)
    2∠BOC = 180° [from (i)]
    ∴ ∠BOC = 90°
    Thus, it is verified that in a rhombus, diagonals are not equal but bisect each other at 90°.

Case IV:

  1. Make a square by paper folding on a glazed paper. Name it as PQRS. Join PR and SQ.
  2. Draw and cut replicas of ∆PQS and ∆PQR.
    CBSE Class 9 Maths Lab Manual – Comparison of Diagonals in Different Quadrilaterals 9
  3. Place two replicas along their diagonals SQ and PR. Here, we observe that both diagonals overlap each other completely. Thus, diagonal SQ = diagonal PR.
  4. Draw and cut replicas of ∆POQ and ∆POS. Place these replicas as shown in fig. below.
    CBSE Class 9 Maths Lab Manual – Comparison of Diagonals in Different Quadrilaterals 10
    Observation:
    Here, PQ = SP (sides of a square)
    OP = OP (common side)
    OQ = OS (By observation)
    ∆POQ = ∆POS (By SSS)
    ∴ ∠POQ = ∠POS (C.P.C.T.)
    But ∠POQ + ∠POS = 180° (linear pair angles)
    2∠POQ = 180°
    ∠POQ = 90°
    This implies that in a square, diagonals are equal and bisect each other at 90°.

Observation
By paper folding and cutting activity it is very much clear that rectangle, square, rhombus and parallelogram differ by their diagonal properties.
In parallelogram, diagonals are not equal, in rectangle diagonals are equal, in rhombus diagonals are not equal but bisect each other at 90°, in square, diagonals are equal and bisect each other at 90°.

Result
We verified that, in parallelogram diagonals are not equal, in square diagonals are equal and bisect each other at 90°. In rectangle diagonals are equal and bisect each other at 90°. In rhombus, diagonals are not equal but bisect at 90°. In this way these figures differentiate each other on the basis of their diagonals.

Learning Outcome
Though square, rectangle and rhombus all have the properties of parallelogram but they are different on the basis of their diagonals.

Activity Time
Draw all types of quadrilaterals on the same plane by using different glazed paper.
CBSE Class 9 Maths Lab Manual – Comparison of Diagonals in Different Quadrilaterals 11
Q – Quadrilateral
P – Parallelogram
Re – Rectangle
R – Rhombus
S – Square
We conclude that, all squares are rhombus, rectangle and parallelogram.

Viva Voce

Question 1.
What do you mean by a rectangle ?
Answer:
A parallelogram having one angle as 90°, is called a rectangle.

Question 2.
All squares are rectangles. Is it true ?
Answer:
Yes.

Question 3.
What is the main difference between a square and a rhombus ?
Answer:
In a square, diagonals are equal and in a rhombus, diagonals are not equal.

Question 4.
All squares are rhombuses. Is this true ?
Answer:
Yes.

Question 5.
All rhombus are squares. Is this true ?
Answer:
No.

Question 6.
What are main types of parallelogram ?
Answer:
Rectangle, square, rhombus.

Question 7.
What is the main difference between a rectangle and a square ?
Answer:
In a rectangle, opposite sides are equal and in a square all the four sides are equal.

Question 8.
How can you say that the parallelogram is a rectangle ?
Answer:
If in a parallelogram, one of the angles is 90°, then it becomes a rectangle.

Question 9.
Differentiate between a parallelogram and a rectangle.
Answer:
In a parallelogram, diagonals are not equal and in a rectangle, diagonals are equal.

Multiple Choice Questions

Question 1.
The similarity between a parallelogram and a rectangle in opposite sides are :
(i) equal and parallel
(ii) not equal
(iii) not parallel
(iv) none of these

Question 2.
The difference between a rectangle and a square is in square all sides are:
(i) equal
(ii) not equal
(iii) can’t say
(iv) none of these

Question 3.
Two sides of a parallelogram having no common end points are called its:
(i) diagonals
(ii) adjacent sides
(iii) opposite sides
(iv) none of these

Question 4.
A quadrilateral which has one pair of opposite sides parallel is called a:
(i) trapezium
(ii) square
(iii) rectangle
(iv) none of these

Question 5.
A quadrilateral in which two pairs of adjacent sides are of equal length is known as a:
(i) parallelogram
(ii) kite
(iii) trapezium
(iv) none of these

Question 6.
A diagonal of a parallelogram divides it into two triangles which are:
(i) congruent
(ii) not congruent
(iii) similar
(iv) none of these

Question 7.
In a parallelogram ABCD, if the length of a diagonal is 5cm and ∠ABC = 90°, then the length of other diagonal will be:
(i) 5 cm
(ii) 6 cm
(iii) 7 cm
(iv) none of these

Question 8.
In a parallelogram PQRS, PR and QS are equal and PQ = 6 cm. What is the length of RS ?
(i) 7 cm
(ii) 6 cm
(iii) 3 cm
(iv) none of these

Question 9.
What will be the area of a parallelogram whose base is 6cm and its corresponding altitude is 8cm ?
(i) 48 cm2
(ii) 40 cm2
(iii) 24 cm2
(iv) none of these

Question 10.
Lengths of the adjacent sides of a parallelogram are equal and intersect at 90° and length of the diagonal is 20cm. What is length of the side of the parallelogram?
(i) 2√5 cm
(ii) 5√4 cm
(iii) 10√2 cm
(iv) none of these

Answers

  1. (i)
  2. (i)
  3. (iii)
  4. (i)
  5. (ii)
  6. (i)
  7. (i)
  8. (ii)
  9. (i)
  10. (iii)

Math Lab ManualMath Labs with ActivityMath LabsScience LabsScience Practical Skills

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Third Conditional Sentences Exercises for Class 7 With Answers CBSE

Third Conditional Sentences Exercises for Class 7 With Answers CBSE

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.

Third Conditional Sentences Exercises for Class 7 With Answers CBSE Pdf

We make the third conditional by using the past perfect after ‘if’ and then ‘would have’ and the past participle in the second part of the sentence:
Formation:
if + past perfect, …would + have + past participle

It talks about the past. It’s used to describe a situation that didn’t happen, and to imagine the result of this situation.
Examples:

  • If she had studied, she would have passed the exam, (but, really we know she didn’t study and so she didn’t pass)
  • If I hadn’t eaten so much, I wouldn’t have felt sick, (but I did eat a lot, and so I did feel sick).
  • If we had taken a taxi, we wouldn’t have missed the plane.
  • She wouldn’t have been tired if she had gone to bed earlier.
  • She would have become a teacher if she had gone to university.
  • He would have been on time for the interview if he had left the house at nine.

Presentations:
Read the picture story.
Third Conditional Sentences Exercises for Class 7 With Answers CBSE 1Third Conditional Sentences Exercises for Class 7 With Answers CBSE 2

Answer the following questions.
1. How would players have scored more goals?
2. When would Referee have awarded a penalty kick?
3. How would game have become better?

Third Conditional Sentences Exercises With Answers for Class 7 CBSE

A. Complete the Third Conditional by putting the verbs into the correct form. The first one has been done for you.

1. If you (study) had studied for the test, you (pass) would have passed it.
2. If you (ask) _____________ me, I (help) _____________ you.
3. If we (go) _____________ to the cinema, we (see) _____________ my friend Jatin.
4. If you (speak) _____________ English, she (understand) _____________.
5. If they (listen) _____________ to me, we (be) _____________ home earlier.
6. I (write) _____________ you a postcard if I (have) _____________ your address.
7. If I (not/break) _____________ my leg, I (take part) _____________ in the contest.
8. If it (not/start) _____________ to rain, we (walk) _____________ to the museum.
9. We (swim) _____________ in the sea if there (not/be) _____________ so many sharks there.
10. If she (take) _____________ the bus, she (not/arrive) _____________ on time.

B. Put the words in brackets into the correct form to make third conditional sentences.

1. If I (pass) _____________ my driving test last month, I would have bought a car straight away.
2. If I (complain) _____________ in the shop, they might have given me a discount.
3. The job (be done) _____________ much faster if there’d been more people helping. As it was, it took us forever.
4. If the job (not/take) _____________ so long, we would’ve had more time to do other things.
5. I (not/say) _____________ what I said if I had known earlier what her reaction was going to be.
6. I wouldn’t have bought the house if I (know) _____________ it had plumbing issues.
7. If I (be) _____________ in your shoes, I wouldn’t have accepted the offer. You made a big mistake.
8. I (not/start) _____________ the job if I had known it was going to take so long.

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First Conditional Sentences Exercises for Class 7 With Answers CBSE

First Conditional Sentences Exercises for Class 7 With Answers CBSELooking 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.

First Conditional Sentences Exercises for Class 7 With Answers CBSE Pdf

The first conditional has the simple present after ‘if’, then the future simple in the other clause.
Formation:
if + simple present,… will + infinitive

It’s used to talk about things which might happen in the future. Of course, we can’t know what will happen in the future, but this describes possible things, which could easily come true.
Examples:

  • If it rains, I won’t go to the park.
  • If I study today, I’ll go to the party tonight.
  • If I have enough money, I’ll buy some new shoes.
  • She’ll be late if the train is delayed.
  • She’ll miss the bus if she doesn’t leave soon.
  • If I see her, I’ll tell her.

Presentation:
Read the picture story.
Answer the following questions.
1. What are the three duties of Mita?
2. When will Ritu and Pooja make sandwiches?
3. How will the party be great?

First Conditional Sentences Exercises With Answers for Class 7 CBSE

A. Complete the Conditional Sentences (First Conditional) by putting the verbs into the correct form.

1. If you (send) send this letter now, she (receive) will receive it tomorrow.
2. If I (do) __________ this test, I (improve) __________ my English.
3. If I (find) __________ your ring, I (give) __________ it back to you.
4. Payal (go) __________ shopping if she (have) __________ time in the afternoon.
5. Sameer (go) __________ to London next week if he (get) __________ a cheap flight.
6. If her boyfriend (phone/not) __________ today, she (leave) __________ him.
7. If they (study/not) __________ harder, they (pass/not) __________ the exam.
8. If it (rain) __________ tomorrow, I (have to/not) __________ water the plants.
9. You (be able/not) __________ to sleep if you (watch) __________ this scary film.
10. Suman (can/move/not) __________ into the new house if it (be/not) __________ ready on time.

B. Complete the conditional sentences (First Conditional). Remember to use the auxiliary verbs.

1. If it doesn’t rain, we (can/go) __________ swimming tomorrow.
2. If you train hard, you (might/win) __________ the first prize.
3. If we go to Canada next year, we (can/work on) __________ our English.
4. I (may/go) __________ to the disco in the evening if I do the laundry now.
5. If we go on holiday next week, I (not/can/play) __________ tennis with you.
6. If you see Ganesh tomorrow, you (should/tell) __________ him that you love him.
7. If my parents go shopping in the afternoon, I (must/look) __________ after my little sister.
8. He (must/be) __________ a good drummer if he plays in a band.
9. If you are listening to the radio after 10 pm, you (should/turn) __________ volume down.
10. If you like that shirt, you (can/have) __________ it.

C. Write the correct first conditional form of the verbs given in the brackets.

1. If I __________ (go) out tonight, I __________ (go) to the cinema.
2. If you __________ (get) back late, I __________ (be) angry.
3. If we __________ (not/see) each other tomorrow, we __________ (see) each other next week.
4. If he __________ (come), I __________ (be) surprised.
5. If we __________ (wait) here, we __________ (be) late.
6. If we __________ (go) on a holiday this summer, we __________ (go) to Spain.
7. If the weather __________ (not/improve), we __________ (not/have) a picnic.
8. If I __________ (not/go) to bed early, I __________ (be) tired tomorrow.
9. If we __________ (eat) all this cake, we __________ (feel) sick.
10. If you __________ (not/want) to go out, I __________ (cook) dinner at home.

D. Fill in the boxes such that the sentences are in first conditional form.

1. If I __________ (to study), I __________ (to pass) the exams.
2. If the sun __________ (to shine), we __________ (to walk) into town.
3. If he __________ (to have) a temperature, he __________ (to see) the doctor.
4. If my friends __________ (to come), I __________ (to be) very happy.
5. If she __________ (to earn) a lot of money, she __________ (to fly) to New York.
6. If we __________ (to travel) to London, we __________ (to visit) the museums.
7. If you __________ (to wear) sandals in the mountains, you __________ (to slip) on the rocks.
8. If Rita __________ (to forget) her homework, the teacher __________ (to give) her a low mark.
9. If they __________ (to go) to the disco, they __________ (to listen) to loud music.
10. If you __________ (to wait) a minute, I __________ (to ask) my parents.

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CBSE Notes for Class 8 Computer in Action – Exploring More Features of Adobe Photoshop

CBSE Notes for Class 8 Computer in Action – Exploring More Features of Adobe Photoshop

In the previous chapter, we learnt about the Selection tools, the Drawing tools and the Painting tools. In this chapter, we will learn about the Retouching tools and the Type tools. We will also learn about two interesting and useful features of Photoshop—Layers and Filters. Layers let us organise our work while Filters let us enhance the look of an image by adding various effects.

RETOUCHING TOOLS
The Retouching tools let you repair damaged images, apply repeated patterns or enhance the look of an image using various effects. Some of the Retouching tools available in Photoshop are Healing Brush Tool, Spot Healing Brush Tool, Patch Tool, Red Eye Tool, Blur Tool, Sharpen Tool, Smudge Tool, Dodge Tool, Sponge Tool, Burn Tool, Clone Stamp Tool and Pattern Stamp Tool.
Let us learn about some of these tools in detail.
cbse-notes-for-class-8-computer-in-action-exploring-more-features-of-adobe-photoshop-(131-1)
The Healing Brush Tool allows you to repair imperfections such as scratches, blemishes and marks in an image. While working with this tool, you pick up sample pixels (pixels to be used for repairing) from the adjoining portion of an image. The Healing Brush Tool matches the texture, lighting, transparency and shading of the sampled pixels and applies them to the pixels that are being repaired.

The steps to use the Healing Brush Tool are:
Step 1: Select the Healing Brush Tool.
Step 2: Select the appropriate options for the Healing Brush Tool in the Options bar (Fig. 8.1).
cbse-notes-for-class-8-computer-in-action-exploring-more-features-of-adobe-photoshop-(132-1)
These options include:

  • Brush Picker: To set the size of the brush tip.
  • Source: To specify whether to pick up sampled pixels from the image (Sampled) or use pre-defmed patterns.
  • Aligned: To specify the sampling point to be used for repairing. If you select this option, you can release the mouse button without losing the current sampling point. If you deselect this option, the sampled pixels are always taken from the initial sampling point.

Step 3: Hold down the Alt key. The cursor shape changes to a target symbol. Click on the area close to the area to be repaired to pick up the sampled pixels.
Step 4: Click and drag over the area to be repaired. The image gets repaired (Fig. 8.2 and Fig. 8.3).
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The Spot Healing Brush Tool works in a similar manner to the Healing Brush Tool except that it does not require the sampling point to be set. It automatically picks up the sampled pixels from around the area to be retouched. This tool can be used to quickly remove spots, blemishes and other marks from photographs.
The steps to use the Spot Healing Brush Tool are:
Step 1: Select the Spot Healing Brush Tool.
Step 2: Select the appropriate options in the Options bar (Fig. 8.3). One of the options includes choosing an appropriate Type option.
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The Type options include:
(a) Content-Aware: Choosing this option uses actual content from the image close to the flaw. You can use this option when removing large items such as scratches from your image.
(b) Create Texture: Choosing this option uses all the pixels in the selection to create a texture that can be used to fix the area.
(c) Proximity Match: Choosing this option makes the Spot Healing Brush Tool use the pixels around the edge of the selection to pick the patch for repairing the selected area.
Step 3: Click on the area you want to fix (Fig. 8.4a and B).
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The Clone Stamp Tool lets you duplicate the parts of an image by setting a sampling point in the image to be cloned. The cloned image can be drawn over another image or part of the same image.
The steps to use the Clone Stamp Tool are:
Step 1: Choose the Clone Stamp Tool.
Step 2: Click the appropriate settings in the Options bar (Fig. 8.5). These settings may include choosing a Brush Size Opacity value or setting the Aligned checkbox.
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Step 3: Hold down the Alt key. The cursor shape changes to a target symbol. Click on the image to be cloned to set the sampling point.
Step 4: Click and drag where you want the cloned image to appear. When you draw, a plus sign (+) appears on the original image while a corresponding circle appears on the cloned image (Fig. 8.6a and b).
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A pattern is usually a design made up of an image that is repeated or tiled. The Pattern Stamp Tool lets you fill an area with a selected pattern. Photoshop comes with a variety of preset patterns. You can select a preset pattern from the Photoshop library or create your own pattern.
The steps to use the Pattern Stamp Tool are:
Step 1: Select the Pattern Stamp Tool.
Step 2: Set appropriate options such as Brush Size, Mode, Opacity and Flow for the Pattern Stamp Tool in the Options bar (Fig. 8.7).
Step 3: Select a pattern from the Pattern Picker in the Options bar.
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Step 4: Place the mouse pointer inside the area where you want to apply the pattern and drag the mouse. The area of the image across which you drag the mouse gets filled with the pattern (Fig. 8.8).
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These tools let you change the appearance or the focus of selected portions of the image.
The Blur Tool softens the selected portions of an image giving it a blurred effect. This tool is useful in situations when you want to moderate or soften the focus of some areas of an image.
The Sharpen Tool is the opposite of the Blur Tool. This tool lets you improve the clarity of an image by sharpening the edges of selected portions of an image.
The Smudge Tool gives an effect of spreading the paint across the image as if you have dragged your finger through wet paint. This tool picks up the colour from where the stroke begins and pushes it in the direction you drag your mouse.
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The steps to use the Blur, Sharpen and Smudge tools are:
Step 1: Select the Blur Tool, the Sharpen Tool or the Smudge Tool from the Tools panel.
Step 2: Set the Brush Size and Blending Mode for the tool in the Options bar.
Step 3: Drag the mouse pointer over the portion of the image you want to blur, sharpen or smudge (Fig. 8.10a and b, Fig. 8.1 la and b).
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The Dodge Tool is used to lighten the areas of an image whereas the Burn Tool is used to darken the areas of an image.
The steps to use the Dodge tool or the Burn Tool are:
Step 1: Select the Dodge Tool or the Burn Tool.
Step 2: In the Options bar, set the appropriate Brush Size and select an appropriate Range option and the Exposure Level.
Step 3: Drag the mouse pointer over the area of the image you want to lighten or darken (Fig. 8.12a, b and c).
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The Type Tools are used for inserting text in Photoshop. You can format the text in many ways such as changing its font family , size, style, colour, alignment, horizontal or vertical orientation, indentation, line spacing and much more. You can also warp the shape of the text in a number of interesting ways such as that of a wave, a flag or an arc.
Note: When you insert text in Photoshop, it is created on a separate layer called the Type Layer. You will learn more about layers later in this chapter.

The Type Tools available in the Tools panel that we will discuss in this chapter are:

  • Horizontal Type Tool inserts text in the horizontal direction.
  • Vertical Type Tool inserts text in the vertical direction.

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The steps to use the Type Tool are:
Step 1: Open the image.
Step 2: Select the Horizontal Type Tool or the Vertical Type Tool.
Step 3: Set the appropriate options such as font family, size, style, alignment and text colour for the Type Tool in the Options bar (Fig. 8.14 and Fig. 8.15).
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Step 4: Click to set the insertion point anywhere on the image.
Step 5: Enter the desired text.
Step 6: Accept changes to the text by clicking the Commit button or cancel the operation by pressing the Cancel button in the Options bar.
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Warping Text
The steps to be followed for warping the text are:
Step 1: Place the cursor anywhere in the already written text.
Step 2: Select the Type tool.
Step 3: Click the Create warped text %, button in the Options bar. This displays the Warp Text dialog box (Fig. 8.16).
Step 4: Choose a warp style from the Style drop-down list.
Step 5: Select the orientation of the warp style—Horizontal or Vertical.
Step 6: If desired, specify values for additional options given in the Warp Text dialog box.
Step 7: Click OK to apply the warp style.
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The Eraser Tool erases pixels as you drag it across an image. Pixels are erased to transparency or to the background colour if the layer is locked. There are three variants of this tool—Eraser Tool, Background Eraser Tool and Magic Eraser Tool (Fig. 8.18).
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The Background Eraser Tool allows you to erase the background colour from an image or a layer. You will learn more about layers later in this chapter. The Background Eraser Tool picks up the sample colour when you click on the image and erases this colour as you drag the mouse (Fig. 8.19).
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On the other hand, the Magic Eraser Tool erases all areas that share similar coloured pixels. When using this tool, click on the area containing the colour to be removed from the image. This erases all the coloured pixels within a set tolerance. You can associate the functionality associated with Magic Eraser Tool to using the Magic Wand Tool and then pressing Delete.
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The steps to use the Eraser Tools are:
Step 1: Select the Eraser Tool, the Background Eraser Tool or the Magic Eraser Tool.
Step 2: Set the appropriate options for the eraser tools in the Options bar.
Step 3: Drag over the area you want to erase when using the Eraser or the Background Eraser Tool.
When using the Magic Eraser Tool, click on the part of the image you want to erase (Fig. 8.20).

Practice Zone
Which Photoshop tool will you use to

  1. duplicate a part of an image by setting the sampling point in the image?
  2. quickly remove blemishes and other marks in photos without setting the sampling point?
  3. remove all areas that share similar pixels in an image?
  4. darken certain areas of an image?
  5. give an effect of spreading paint across the image?
  6. moderate or soften the focus of some areas of an image?

Scan any of your old photographs. Make use of various Retouching Tools to   remove any scratches, marks and so on, in your photographs to give it a new and fresh look.

LAYERS
Layers can be thought of as transparent sheets mounted on the top of each other.
Layers let you work on an individual part or an element of an image without affecting the other parts or elements. You can change the composition of an image by changing the order and properties of layers. Elements placed on higher layers are displayed above the elements placed on lower layers.
Look at the graphic in Figure 8.21. To you, it may look a single, flat graphic but it is actually a combination of various elements placed on different layers. In the given graphic, the lady, flag, text and background are all placed on different layers (Fig. 8.22).
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When you open a new image file with a white or a coloured background, the bottom-most image in the Layers panel is called Background. An image can have only one background. You cannot change the order of the background layer. You can add more layers, delete layers, show/hide layers, lock layers and use different layer styles to add sophisticated effects to your image.
Let us learn more about working with layers.

Working with Layers
Let us now learn about adding new layers, deleting layers, renaming layers, hiding and showing layers, changing the order of layers and layer effects in this section.
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Adding a new layer
You can add a new layer by using any one of the following methods.
Click the New Layer button Ü in the Layers panel.
OR
Choose Layer → New → Layer.
A new layer with the name Layerl gets inserted above the selected layer.

Renaming a layer
You can rename a layer by double-clicking on the layer name in the Layers panel and typing a new name.

Deleting a layer
You can delete one or more layers by using any one of the following methods.
Select the layer and click the Delete Layer  button in the Layers panel.
OR
Choose Layer ? Delete ? Layer.
OR
Drag the Layer to the Delete Layer button.

Showing and hiding layers
To hide the layer contents, click the Eye icon next to a layer. Click in the Eye icon again to display the contents of the layer again.

Changing the order of layers
The elements that are placed on the higher layers are displayed above the elements placed on the lower layers. To change the placement of elements in an image, you can rearrange the layers containing them in the Layers panel. To change the order of layers, drag the layer to an appropriate position in the Layers panel.

Layer effects
Photoshop offers various layer effects that allows you to enhance the look of the contents of a layer. Some of these effects include shadow, glow, bevel, emboss and overlay.
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The steps to apply the layer effects are:
Step 1: Select a layer in the Layers panel (Fig. 8.23).
Step 2: Click the Layer Styles button at the bottom of the Layers panel and choose an effect from the list, or Choose Layer ? Layer Style.
Step 3: The Layer Style dialog box appears (Fig. 8.24). Choose the desired effect by clicking the corresponding check boxes on. the left side of the dialog box.
Step 4: Set appropriate options for the selected effect on the right side of the dialog box.
Step 5: Click OK to apply the effect.
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When you apply Layer effects, an ‘fx’ icon appears to the right of the layer name in the Layers panel. You can click on this icon to display the list of the effects applied on the layer (Fig. 8.25 and 8.26).
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Create a beautiful scenery/greeting card/collage by placing various elements of an image on different layers. Apply layer effect to various elements of the | image. Also, make use of Type Tool to provide appropriate caption to your i
scenery/greeting card/collage.

Practice Zone
State whether the following statements are True or False.

  1. Layers let you work on an individual part of an image without affecting others.
  2. You cannot change the stacking order of layers.
  3. When you insert text in Photoshop, it is created on a separate layer called the Type Layer.
  4. Elements placed on higher layers are displayed below the elements placed on lower layers.
  5. You cannot apply effects on layers.
  6. An image can have only one background.

FILTERS
Filters let you change the appearance of an image by adding special effects to it. Filters are available under the Filter menu. Photoshop offers various categories of Filters. For example, you can use the Stylize filters to give a painted effect to your images, the Render filters to create 3D shapes, reflections in an image and so on.
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Applying Filters
You can apply a filter to an entire layer, or a Selected portion of a layer. The steps to be followed are:
Step 1: Select the entire layer or a particular portion of a layer.
Step 2: Choose the desired filter from the Filter menu (Fig. 8.27).
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Step 3: Some filters have a dialog box associated with them. If the dialog box appears, set the desired options in the dialog box to apply the filter. If no dialog box appears, the selected filter is applied directly to the image (Fig. 8.28 and Fig. 8.29).
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Filter Gallery
Filter Gallery offers a convenient way of applying multiple filters on the image or applying individual filters more than once on an image.
To apply a filter or multiple filters on an image using the Filter Gallery, follow the given steps.
Step 1: Select the entire image layer or a particular portion of a layer to which the filter needs to be applied.
Step 2: Choose Filter ? Filter Gallery (Fig. 8.30). The Filter Gallery dialog box gets displayed.
Step 3: The Filter Gallery dialog box arranges filters by category. Click the inverted triangle next to the filter category to display the list of filters. Choose a filter name to add the first filter.
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Step 4: Choose the desired settings for the selected filter. The applied filter gets added to the list at the lower-right corner of the Filter Gallery dialog box (Fig. 8.31).
Step 5: To apply additional filters to the image, click the New Effect Layer icon. Choose another filter to apply. Repeat this procedure to add more filters.
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Step 6: To remove the already applied filters, select a filter in the applied filter list and click the Delete icon.
Step 7: If you are satisfied with the current image settings, click on OK.

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Informal Letter Writing Topics For Class 6 Format, Examples, Topics, Exercises

Informal Letter Writing Topics For Class 6 Format, Examples, Topics, Exercises

Informal Letter Writing Topics For Class 6 Format, Examples, Topics, Exercises

Writing informal letters is an essential skill that every student should master. This type of letter is personal and friendly, and it is written to someone you know, such as a friend, relative, or acquaintance. The format of an informal letter is less rigid than that of a formal letter, and it allows for more creativity and individuality. In this article, we will provide you with a format for writing informal letters, some examples, and topics for exercises.

Format For Informal Letter Writing Topics For Class 6:

1. Date: Write the date on the top right-hand corner of the page.
2. Salutation: Begin the letter with a friendly greeting, such as “Dear” or “Hello.” Use the person’s first name if you know them well, or their title and last name if you are not as familiar with them.
3. Introduction: Start the letter by stating why you are writing. For example, you might say “I hope this letter finds you well” or “I wanted to write to you to tell you about my recent trip.”
4. Body: This is the main part of the letter, where you can write about anything you like. You might talk about your recent experiences, ask about the recipient’s life, or share a funny story.
5. Closing: End the letter with a friendly closing, such as “Take care” or “Yours truly.” You can also include a phrase like “Write back soon” or “Can’t wait to hear from you.”
6. Signature: Sign the letter with your first name or a nickname.

Also Read: Letter Writing Class 12 AHSEC

Example Of An Informal Letter Writing Topics For Class 6:

Dear Sarah,

I hope this letter finds you well. It has been a while since we last spoke, and I wanted to write to catch up and see how you are doing. I have been keeping busy with school and work, but I have also found some time for fun and relaxation.

Last weekend, I went on a camping trip with some friends. We hiked in the mountains and slept under the stars. It was amazing to be out in nature and away from the hustle and bustle of the city. I even saw a bear, but don’t worry, we kept our distance!

What have you been up to lately? How is your job going? Have you taken any trips or tried any new hobbies? I would love to hear all about it.

Take care,
Emily

Example Of An Informal Letter Writing Topics For Class 6

Topics For Informal Letter Writing Topics For Class 6 Exercises:

1. Write a letter to a friend who has moved away and tell them about what has been happening in your life.
2. Write a letter to a family member and share a special memory that you have with them.
3. Write a letter to your favorite teacher and thank them for all that they have done for you.
4. Write a letter to a pen pal from another country and ask them about their culture and traditions.
5. Write a letter to a famous person and tell them how they have inspired you.
6. Write a letter to a grandparent and share a recipe that you have learned how to make.
7. Write a letter to a sibling and reminisce about a funny childhood memory.
8. Write a letter to a neighbor and offer to help them with a task or project.
9. Write a letter to your future self and tell them about your hopes and dreams.
10. Write a letter to your pet and tell them how much they mean to you.

Conclusion On Informal Letter Writing Topics For Class 6

Informal letter writing is a valuable skill that can be developed with practice. By following the format outlined above and using some of the topics provided, students can become confident and expressive writers.

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Letter Writing Class 12 AHSEC Format, Examples, Topics, Exercises

Letter Writing Class 12 AHSEC Format, Examples, Topics, Exercises

Letter Writing Class 12 AHSEC Format, Examples, Topics, Exercises

Letter writing is an important part of communication that is essential for both personal and professional purposes. In Class 12 AHSEC (Assam Higher Secondary Education Council), letter writing is an important component of the English syllabus. Students are required to learn the format, examples, topics, and exercises related to letter writing. In this article, we will discuss the various aspects of letter writing for Class 12 AHSEC.

Format Of Letter Writing Class 12 AHSEC:

The format of a letter varies depending on its purpose and the relationship between the sender and the recipient. However, the basic format of a letter includes the following elements:

1. Sender’s address: The sender’s address should be written at the top right corner of the letter. It should include the sender’s name, street address, city, state, and zip code.
2. Date: The date should be written below the sender’s address. It should be written in the format of month, date, and year.
3. Recipient’s address: The recipient’s address should be written below the date. It should include the recipient’s name, title, company or organization name, street address, city, state, and zip code.
4. Salutation: The salutation should be written below the recipient’s address. It should be a formal greeting that addresses the recipient by name and title. For example, “Dear Mr. Johnson,” or “Dear Professor Smith,”.
5. Body of the letter: The body of the letter should be written below the salutation. It should include the main content of the letter.
6. Closing: The closing should be written below the body of the letter. It should be a formal closing that expresses the sender’s respect and goodwill towards the recipient. Examples include “Sincerely,” or “Respectfully,”.
7. Signature: The sender’s signature should be written below the closing. It should be followed by the sender’s typed name and title.

Also Read: Letter Writing For Class 8 Formal

Some Examples Of Letter Writing Class 12 AHSEC:

1. Formal Letter: Job Application

Sender’s Address
City, State
Zip Code
Date

Recipient’s Address
City, State
Zip Code

Dear Sir/Madam,

I am writing to apply for the position of Marketing Manager advertised in the newspaper on [date]. I have attached my resume and a cover letter for your consideration.

I have [number] years of experience in marketing and sales, and I am confident that my skills and experience make me an ideal candidate for the job. I have a track record of delivering results, and I am able to work under pressure and meet deadlines.

Thank you for considering my application. I look forward to hearing from you soon.

Sincerely,

[Your Name]

2. Informal Letter: Letter to a Friend

Sender’s Address
City, State
Zip Code
Date

Recipient’s Address
City, State
Zip Code
Dear [Friend’s Name],

How are you? It’s been a long time since we last talked. I hope you are doing well.

I wanted to write to you and tell you about my recent trip to [destination]. It was an amazing experience! The weather was perfect, and the scenery was breathtaking. I visited [place1], [place2], and [place3]. I especially enjoyed [activity or attraction] and [activity or attraction].

I also tried the local cuisine, and it was delicious! I had [dish1], [dish2], and [dish3]. I wish I could have brought some back for you to try.

Overall, it was a great trip, and I can’t wait to go back someday. I hope we can plan a trip together soon.

Take care,

[Your Name]

Examples Of Letter Writing Class 12 AHSEC

3. Official Letter: Request for Information

Sender’s Address
City, State
Zip Code
Date

Recipient’s Address
City, State
Zip Code

Dear Sir/Madam,

I am writing to request information regarding [topic]. I am interested in [details about what you want to know], and I would appreciate it if you could provide me with the following information:

[Information request 1]
[Information request 2]
[Information request 3]

I would be grateful if you could send me this information as soon as possible. If there are any costs involved, please let me know.

Thank you for your attention to this matter.

Sincerely,

[Your Name]

4. Social Letter: Thank You Note

Sender’s Address
City, State
Zip Code
Date

Recipient’s Address
City, State
Zip Code

Dear [Name],

I wanted to take a moment to thank you for [reason for the thank-you note]. Your [gift, kindness, or other gesture] meant so much to me.

I appreciate your thoughtfulness and your support. You are a wonderful friend, and I am grateful to have you in my life.

Thank you again for everything.

Warmly,

[Your Name]

Topics For Letter Writing Class 12 AHSEC:

The topics for letter writing in Class 12 AHSEC can vary depending on the type of letter and the context. Some common topics for letter writing are:

1. Formal letters:

• Application for a job or internship
• Complaint letter about a product or service
• Inquiry about a product or service
• Request for information
• Business proposal letter

2. Informal letters:

• Letter to a friend or family member
• Letter to a pen pal
• Letter about a recent vacation or trip
• Letter about a special event or occasion
• Letter expressing gratitude or appreciation

3. Official letters:

• Letter to a government official
• Letter to a municipality
• Letter to a passport office
• Letter to a tax department
• Letter to an embassy or consulate

4. Social letters:

• Invitation to a party or event
• Thank-you note for a gift or kindness
• Congratulatory letter for graduation or achievement
• Letter of sympathy or condolences
• Letter to a sponsor or donor

Exercises For Letter Writing Class 12 AHSEC:

To improve their letter-writing skills, students in Class 12 AHSEC can practice various exercises. Here are some exercises that students can try:

1. Practice writing different types of letters:

Students can practice writing different types of letters, such as formal, informal, official, and social letters. They can use the format and examples provided above as a guide.

2. Use different vocabulary and expressions:

Students can use a variety of vocabulary and expressions to make their letters more interesting and engaging. They can use a thesaurus or dictionary to find synonyms and antonyms for common words.

3. Proofread and edit their letters:

Students should always proofread and edit their letters before submitting them. They can check for spelling and grammar errors, punctuation mistakes, and sentence structure.

4. Write letters on current events:

Students can practice writing letters on current events such as social issues, politics, and environmental concerns. They can express their opinions, ideas, and solutions to the problem.

5. Write letters in response to prompts:

Students can practice writing letters in response to prompts given to them by their teacher. These prompts can be on a variety of topics and can help students improve their writing skills.

Conclusion On Letter Writing Class 12 AHSEC:

Letter writing is an important skill that students in Class 12 AHSEC need to master. It requires the ability to communicate effectively, express ideas clearly, and use appropriate language and expressions. By practicing different types of letters, using different vocabulary and expressions, and proofreading and editing their work, students can improve their letter-writing skills and become better communicators.

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Letter Writing For Class 8 Formal Format, Examples, Topics, Exercises

Letter Writing For Class 8 Formal Format, Examples, Topics, Exercises

Letter Writing For Class 8 Formal Format, Examples, Topics, Exercises

As a student in class 8, it is important to learn the art of letter writing. This skill will be useful not only in school but also in personal and professional life. In this article, we will discuss the formal format of letter writing, provide examples of different types of letters, suggest topics for letter-writing exercises, and offer tips on how to improve your letter-writing skills.

Formal Format Of Letter Writing For Class 8 Formal:

A formal letter is written in a prescribed format. It is important to follow the format to maintain professionalism and clarity. Here is the format of a formal letter:

1. Sender’s Address: The sender’s address is written at the top of the letter. It includes the name of the sender, their address, and the date. The sender’s address is followed by a line break.
2. Receiver’s Address: The receiver’s address is written below the sender’s address. It includes the name and address of the receiver. The receiver’s address is followed by a line break.
3. Salutation: The salutation is the greeting that begins the letter. It should be formal and address the receiver appropriately. For example, “Dear Mr. Smith,” or “Dear Madam,”. If you do not know the name of the recipient, use “Dear Sir/Madam,”.
4. Body: The body of the letter is where the message is conveyed. It should be written in paragraphs, with each paragraph addressing a specific topic. The first paragraph should introduce the purpose of the letter. The subsequent paragraphs should provide details and explanations.
5. Closing: Closing is a polite way to end the letter. Common closings include “Sincerely,” or “Yours faithfully,”. After the closing, leave a few lines for the signature.
6. Signature: The sender’s signature should be written below the closing. If the letter is being typed, leave a space for the signature.

Also Read: Letter Writing Class 12 AHSEC

Examples Of Different Types Of Letter Writing For Class 8 Formal:

1. Formal Letter of Complaint:

Sender’s Address:
Date:

Receiver’s Address:

Dear Sir/Madam,

I am writing to complain about the poor service I received from your company. On [date], I purchased a product from your store, but it was faulty. I returned the product on [date], but the replacement I received was also faulty.

I have contacted your customer service department several times, but no action has been taken to resolve my issue. I would like a full refund for the faulty product and compensation for the inconvenience caused.

I look forward to hearing from you soon.

Sincerely,
[Sender’s Name]

2. Formal Letter of Application:

Sender’s Address:
Date:

Receiver’s Address:

Dear Sir/Madam,

I am writing to apply for the position of [Job Title] advertised on [Website/Newspaper]. I am confident that my skills and experience make me an ideal candidate for the role.

I have a degree in [Degree Subject] from [University Name]. I have [Number of Years] of experience in [Industry/Field]. I am skilled in [Skill 1], [Skill 2], and [Skill 3], which I believe are essential for this position.

I have attached my resume and a cover letter for your consideration. Thank you for your time and I look forward to hearing from you.

Sincerely,
[Sender’s Name]

Formal Letter of Application

3. Formal Letter of Recommendation:

Sender’s Address:
Date:

Receiver’s Address:

Dear Sir/Madam,

I am writing to recommend [Name of Recipient] for [Reason for Recommendation]. I have known [Name of Recipient] for [Number of Years] and during this time, I have witnessed their dedication, hard work, and skills.

[Name of Recipient] is a skilled [Profession/Job Title] who is always willing to go the extra mile to ensure customer satisfaction. They have excellent communication skills and are able to work well under pressure. They are a team player who is always willing to help their colleagues.

I believe that [Name of Recipient] would be an asset to any team or organization. I highly recommend them for [Reason for Recommendation].

Sincerely,
[Sender’s Name]

Topics For Letter Writing For Class 8 Formal Exercises:

1. Write a letter to your principal requesting permission to organize a cultural event in your school.
2. Write a letter to the editor of a newspaper expressing your concerns about environmental pollution in your city.
3. Write a letter to a friend thanking them for their hospitality during your recent visit.
4. Write a letter to a company requesting information about their products.
5. Write a letter to a government official urging them to take action on a social issue that you are passionate about.

Tips On How To Improve Your Letter Writing For Class 8 Formal Skills:

1. Use clear and concise language.
2. Use proper grammar and punctuation.
3. Use a formal tone and appropriate salutations.
4. Use paragraphs to organize your thoughts and ideas.
5. Proofread your letter before sending it.
6. Be polite and respectful in your tone.
7. Keep the letter brief and to the point.

Conclusion On Letter Writing For Class 8 Formal

Letter writing is an important skill that can help you communicate effectively in personal and professional settings. By following the formal format, practicing different types of letters, and using these tips, you can improve your letter-writing skills and make a positive impression on your recipients.

Posted in CBSE  • 

CBSE Class 9 Maths Lab Manual – Areas of Two Triangles on the Same Base

CBSE Class 9 Maths Lab Manual – Areas of Two Triangles on the Same Base and between the Same Parallels

Objective
To show that the triangles on the same base and between the same parallel lines are equal in area experimentally.

Prerequisite Knowledge

  1. Familiarity with triangles.
  2. Formula for area of triangle = \(\frac{ 1 }{ 2 }\) x base x height.
  3. Shortest distance between the two parallel lines.

Materials Required
Glazed papers, a pair of scissors, pencil, gluestick, white sheet.

Procedure

  1. Draw any triangle on a glazed paper and name it as ABC.
  2. Cut the triangle and paste it on the white sheet as shown in fig.(i).
    CBSE Class 9 Maths Lab Manual – Areas of Two Triangles on the Same Base 1
  3. Cut another triangle EGH such that EH = BC [fig .(ii)]
    CBSE Class 9 Maths Lab Manual – Areas of Two Triangles on the Same Base 2
  4. Draw a line l at point A such that l is parallel to BC as shown in fig.(iii).
  5. Draw any triangle KBC with the base BC and its vertex K lying on the line l as shown in fig (iii).
  6. Paste ∆EGH on ∆ABC such that EH lies on BC and G does not lie on line l as shown in fig (iii).
    CBSE Class 9 Maths Lab Manual – Areas of Two Triangles on the Same Base 3

Observation
ar(∆ABC) = \(\frac{ 1 }{ 2 }\) x base x height
= \(\frac{ 1 }{ 2 }\) x BC x (⊥distance between || lines l and BC)
= \(\frac{ 1 }{ 2 }\) x BC x AM
ar(∆BKC) = \(\frac{ 1 }{ 2 }\) x BC x (⊥distance between || lines l and BC)
= \(\frac{ 1 }{ 2 }\) x BC x KL
= \(\frac{ 1 }{ 2 }\) x BC x AM (⊥distance between || lines is always same), (KL = AM)
∴ ar(∆ABC) = ar(∆BKC)
ar(∆EGH) = \(\frac{ 1 }{ 2 }\) x base x height
= \(\frac{ 1 }{ 2 }\) x BC x (⊥distance from G to BC)
= \(\frac{ 1 }{ 2 }\) x BC x GN
But, AM ≠ GN
∴ ar(∆ABC) ≠ ar(∆EGH)

Result
We have verified that two triangles on the same base and between the same parallel lines are equal in area.

Learning Outcome
We learnt that areas of two or more triangles are same if they lie on the same base and between the same parallel lines. Triangles having same base but different perpendicular heights are not same and their areas are also not equal.

Activity Time
Students can verify this theorem by graphical and counting method.
[Hint: Draw two triangles on the same base and between the same height and then count the squares covered by two triangles on the graph paper].

Viva Voce

Question 1.
Two triangles are on the same base and same height, area of one of the triangle is 4 cm2. What will be the area of second triangle ?
Answer:
4 cm2

Question 2.
In a triangle, a median divides the triangle in two parts. What will be the area of two triangles, so formed ?
Answer:
Area of two triangles will be same.

Question 3.
If two triangles are having same areas then the triangles will be congruent ?
Answer:
Not necessary.

Question 4.
If two triangles are having same base 4 cm and their area is 12 cm2 and lying between the same parallel lines, what will be the height?
Answer:
6 cm.

Question 5.
Parallelograms on the same base and having equal areas lie between the same parallels. Is the converse true ?
Answer:
Yes, the converse is true.

Question 6.
If a triangle and a parallelogram are on the same base and between the same parallels, then what will be area of triangle ?
Answer:
Area of triangle is equal to half the area of parallelogram.

Question 7.
In the above question, area of parallelogram is 12 cm2, what will be the area of the triangle ?
Answer:
6 cm2

Question 8.
If a triangle and a parallelogram are on the same base and not lie between same parallel lines, then will they have same altitudes ?
Answer:
No, they will not have same altitudes.

Question 9.
If two triangles are on same base and having same areas. What can you say about their heights.
Answer:
Their heights will be same.

Multiple Choice Questions

Question 1.
Triangles ABC and DBC are on the same base BC and with vertices A and D on opposite sides of BC such that ar (∆ABC) = ar (∆DBC). What is the relation between their altitudes ?
(i) equal
(ii) not equal
(iii) altitude of ∆ABC = altitude of ∆BDC
(iv) none of these

Question 2.
D and E are points on sides AB and AC respectively of ∆ABC, such that ar(∆DBC) = ar(∆EBC). Are lines DE and BC parallel to each other ?
(i) yes
(ii) no
(iii) DE = BC
(iv) none of these

Question 3.
In ∆ABC, AB = 8 cm and altitude corresponding to AB is 5cm. In ∆DEF, EF = 10 cm. Find the altitude corresponding to side EF, if ar (∆ABC) = ar(∆DEF):
(i) 8 cm
(ii) 5 cm
(in) 4 cm
(iv) none of these

Question 4.
The area of rectangle ABCD is 50 sq. cm. If P be any point on AB, find area of ∆PCD :
(i) 25 sq.cm
(ii) 100 sq.cm
(iii) 50 sq. cm
(iv) none of these

Question 5.
Find area of triangle whose base is (x – 3) and height is (x + 4) and its area is x2/2:
(i) 72 cm2
(ii) 12 cm2
(iii) 144 cm2
(iv) none of these

Question 6.
In triangle ABC, O is the mid-point on its median AD. If area of ∆ABD is 12 cm2. Find area of ∆ABO:
(i) 12 cm2
(ii) 24 cm2
(iii) 6 cm2
(iv) none of these

Question 7.
In ∆ABC, D, E and F are mid-points of the sides BC, CA, AB respectively. If area of ∆ABC is 144 cm2. What will be the area of triangle DEF ?
(i) 36 cm2
(ii) 12 cm2
(iii) 72 cm2
(iv) none of these

Question 8.
In ∆PQR, M, N, P are mid-points of the sides PQ, QR, RP respectively. If area of ∆PQR is 162 cm2, then what will be the area of parallelogram PNQM ?
(i) 81 cm2
(ii) 41 cm2
(iii) 54 cm2
(iv) none of these

Question 9.
ABDE and BCDE are two parallelograms on the same base ED. AB = BC = DE. If ar(∆BDE) = 75 cm2. What will be area of ACDE ?
CBSE Class 9 Maths Lab Manual – Areas of Two Triangles on the Same Base 4
(i) 75 cm2
(ii) 225 cm2
(iii) 3 cm2
(iv) none of these

Question 10.
AD is a median of ∆ABC. If ar(∆ABD) = x cm2 and ar(∆ABC) = y cm2. Find the relation between x and y:
(i) x – 2y
(ii) y – 2x
(iii) y – x
(iv) none of these

Answers

  1. (i)
  2. (i)
  3. (iii)
  4. (i)
  5. (i)
  6. (iii)
  7. (i)
  8. (i)
  9. (ii)
  10. (ii)

Math Lab ManualMath Labs with ActivityMath LabsScience LabsScience Practical Skills

Posted in CBSE  • 

CBSE Class 9 Science Practical Skills – Density of Solid

CBSE Class 9 Science Practical Skills – Density of Solid

Basic Building Concepts
Density
It is the physical property of a matter that describes how the individual particles of the substance are closely packed together. In other words, it describes the degree of compactness of a substance.
In qualitative manner, the density of a substance is defined as its mass per unit volume, i.e.,
Density(ρ) = \(\frac { Mass(M) }{ Volume(V) }\)
The amount of matter contained in the body is called mass. The mass is measured commonly in grams (g) and its SI unit is kilogram (kg).
The space occupied by the quantity of matter is called volume of the object. It is measured in cubic centimetres (cm3) and its SI unit is m3.
Therefore, unit of density is g/cm3 or kg/m3
1 kg m-3 = 10-3 gcm-3

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

Density of Some Common Substances
The density of a given substance, under specified condition, is always the same. Therefore, it is a characteristic property. It is different for different substances as shown in the following table:

Substances Densities
g cm-3 kg m-3
Air 0.0013 1.30
Ice 0.92 920
Water 1.00 1000
Common Salt (NaCl) 2.16 2160
Aluminium 2.70 2700
Iron 7.80 7800
Silver 10.50 10500
Gold 19.30 19300

From the table, it is clear that the different substances have different densities. Thus density measurements provide a useful tool for identifying substances either molecules of a compound or atoms of an element.
The factor that can affect the density of a material is temperature. When the temperature of a substance increases, its density decreases.
Applications

  • Categorise the substance.
  • Identify the different materials.
  • For building ships and making hot air balloons.
  • Determine the purity of a substance.

Examples

  • Ice floats on water.
  • Oil floats on the surface of water.
  • Stone sinks in liquid (water).

Relative Density
When density of a substance is compared with the density of water, then it is called relative density. Thus relative density of a substance is the ratio of its density to that of water at 4°C having the same volume as that of the substance.
Relative Density(R.D.) = \(\frac { Density\quad of\quad Substance({ \rho  }_{ s }) }{ Density\quad of\quad Water({ \rho  }_{ w })\quad at\quad { 4 }^{ 0 }C }\)
or
R.D. = \(\frac { { \rho  }_{ s } }{ { \rho  }_{ w } }\)
Since the relative density is expressed in terms of ratio, it has no unit.
If the relative density of a substance is more than 1, the substance would sink in water. For example, relative density of iron is 2.70, so it sinks in water.
If R.D. < 1, the substance or object floats on the surface of water. For example, ice block.

Spring Balance
It is simply a spring whose one end is attached to a rigid support and other free end with a hook attached to another object.
Working Principle of Spring Balance
It works on the principle of elasticity. Applied force to stretch a spring is directly proportional to the change in length from its mean position. Therefore, the scale marking on the spring scale are equally spaced. Mathematically,
F ∝ x
or F = -kx
where F is the force exerted by a spring, and x is the displacement of the end of a spring from its equilibrium position. The proportionality constant ‘k’ is called ‘spring constant’. More the spring constant, harder the spring to stretch out.
Negative sign indicates that applied force and spring stretched distance both are in opposite directions as shown below.
CBSE Class 9 Science Practical Skills - Density of Solid 1
On hanging the object from the hook, spring will stretch. Let the change in length of spring be x. The mass of the object is pulled down by force of gravity (mg) and pulled up by the spring force (F). These forces balance each other, i.e., F = mg. Thus with the help of a spring, we can measure the weight of the body not the mass of the body. If the scale of spring balance is calibrated in gram, then the weight of solid is measured in gram-weight. Weight of the body in gram-weight is numerically equal to the mass of the solid.

Uses

  • Spring balance or spring scale is used in physics as a basic accelerometer.
  • For weighing heavy loads in industry.
  • To measure the weight of materials carried on a conveyor belt.

Aim
To determine the density of a solid (denser than water) by using a spring balance and a measuring cylinder.

Apparatus Required
A metallic object (any shape), iron stand, a spring balance, a measuring cylinder (preferably 0-250mL)

Theory
Mass per unit volume of a substance is called the density of a given substance.
Let M be the mass of a given substance/object and V be its volume. Its density ρ is given by
ρ = \(\frac { M }{ V } =\frac { Mass\quad of\quad Object }{ Volume\quad of\quad Object }\)
Its S.I. unit is kg m-3.
Let the weight of object measured by the spring balance in air = W g-wt.
Initial volume of water in measuring cylinder = V1 mL.
Final volume of water in measuring cylinder when object is fully immersed in water = V2 mL.
Volume of object = Volume of displaced water = (V2 – V1) mL
Therefore, density of object (ρ) = \(\frac { W }{ { V }_{ 2 }-{ V }_{ 1 } }\) g cm-3

Procedure

  1. Hang the spring balance vertically with the help of iron stand as shown in Fig. 2.2.
  2. Find its least count by using the given formula:
    Least Count = \(\frac { Rangeofgiven\quad spring\quad balance }{ Total\quad number\quad ofdivisions }\)
  3. Check the zero error (if any) and record it with proper sign.
    This is the reading of spring balance when no weight is suspended from its lower hook.
    CBSE Class 9 Science Practical Skills - Density of Solid 2
    Measurement of weight of a given metallic object:
  4. Hang the metallic object with the lower hook of the spring balance as shown in Fig. 2.3.
  5. Take the reading of spring balance when the metallic object becomes static.
  6. Obtain the true weight of the given metallic object by subtracting the zero error (if any) from the observe weight.
  7. Repeat the experiment thrice and find its mean weight.
    Measurement of the volume of a given metallic object:
  8. Pour some water into the measuring cylinder and record the initial level of water (lower position of meniscus) as shown in Fig. 2.4. Let the initial volume be V1 (mL).
  9. Remove the metallic object from the spring balance and tie it by a thin strong thread and immerse it fully in the water in measuring cylinder.
  10. Note down the new position of meniscus V2 (mL) in the measuring cylinder as shown in Fig. 2.5. The level of water rises up because the immersed object displaces water from its initial level.
  11. Obtain the volume of the immersed metallic object by subtracting the two position of meniscus (water level) i.e. V2 – V1
  12. Repeat the experiment thrice and find its mean volume.
    CBSE Class 9 Science Practical Skills - Density of Solid 3

Observations
Least count of spring balance: ………… g wt.
Zero error of the spring balance: …………. g wt.
Least count of measuring cylinder: ……….mL
Table: Measurement of weight of a given metallic object.

S.No. Reading of spring balance Weight of metallic object
(without object) W1 (g wt.) (with object) W2 (g wt.) Weight of object observed
W2 – W1
(g wt.)		 True weight of object W = (W2 – W1) – (Zero error) (g wt.)
1. W’1 =
2. W’2 =
3. W’3 =

Mean weight of given metallic object = \(\frac { { W }_{ 1 }^{ ‘ }+{ W }_{ 2 }^{ ‘ }+{ W }_{ 3 }^{ ‘ } }{ 3 }\) = ………..g wt.
Mass of the given metallic object by spring balance, (M) = ………….. g.
Table: Measurement of volume of a given metallic object

S.No. Initial position of meniscus
(Without metallic object)
V1 (mL)		 Final position of meniscus
(Metallic object immersed) V2 (mL)		 Volume of object
V = V2 – V1 (mL)
1. V’1 =
2. V’2 =
3. V’3 =

 Mean volume V = \(\frac { { V }_{ 1 }^{ ‘ }+{ V }_{ 2 }^{ ‘ }+{ V }_{ 3 }^{ ‘ } }{ 3 }\) = ………….mL

Calculations
True mass of given object = ………… g
Volume of given object = …………..mL
Density of a given metallic object = \(\frac { Mass\quad of\quad Object }{ Volume\quad of\quad Object } =\frac { M }{ V }\) g/mL = ……….g/mL = ………… kg m-3 ( 1000 kg m-3 = 1 gmL-1)

Result
The density of the given solid (heavier than water) = ……… kg m-3.

Precautions

  1. Spring balance should be sensitive, stable and error free.
  2. The horizontal pointer should move freely along the scale of spring balance.
  3. Spring balance must be suspended vertically from fixed support of iron stand.
  4. Reading should be taken only when oscillation of hanging object dies completely.
  5. Eye should be kept in line (exactly horizontal) while taking the reading of spring balance as well as measuring cylinder as shown in figs. 2.6 and 2.7.
  6. Solid object should be dried completely before measuring mass in air and when allowed to immersed in water.
  7. While measuring the volume of object, the object should not touch sides and bottom of a measuring cylinder.
  8. The water of the measuring cylinder should not fall out during immersing of solid object.
    CBSE Class 9 Science Practical Skills - Density of Solid 4

Source of Error

  1. Least count of spring balance may be higher.
  2. Spring of spring balance may be permanently stretched.
  3. Solid object may not be completely dried.
  4. The eye may not be in the proper level of meniscus while measuring the volume of solid object.

Interactive Session

Question 1.
What is the aim of your object?
Answer:
To determine the density of a given solid (denser than water) by using spring balance and measuring cylinder.

Question 2.
What is the unit of density?
Answer:
g cm-3 or kg m-3.

Question 3.
What is the relation between mL and cm3?
Answer:
1 mL = 1 cm3.

Question 4.
Is there any effect of temperature on the density?
Answer:
Yes, density of a substance decreases with the rise in temperature.

Question 5.
Why?
Answer:
Due to rise in temperature, volume of the body increases and hence density decreases.

Question 6.
What is the density of water at 4°C?
Answer:
It is 103 kg/m3 or 1 gm/cm3.

Question 7.
What is the difference between mass and weight?
Answer:
Mass is a measure of the quantity of matter, which is constant all over the universe. Weight is proportional to the mass but depends on the gravity of the planet.

Question 8.
What is weight?
Answer:
Weight is the force exerted on a body by gravitational attraction of the planet (earth).

Question 9.
Convert 500 g mass into unit of force.
Answer:
Unit of force is newton (N)
F = mg = \(\frac { 500\quad kg }{ 1000 } \times 9.8\) m/s2 = 4.9 kg ms-2 = 4.9 N

Question 10.
Name the device which measures the mass and weight.
Answer:
Mass is measured by physical balance. Weight is measured by spring balance.

Question 11.
What is the working principle of spring balance?
Answer:
The extension in the length of spring when the body is suspended from its free end, is directly proportional to the weight of the body.

Question 12.
You stated that weight was measured by spring balance, then how can you deduce mass from weight?
Answer:
The weight of the body in gram-weight is numerically equal to the mass of solid,
i. e., 100 gwt. = 100 gf = 100 g. or 100 kgwt. = 100 kg f = 100 kg.

Question 13.
How can we minimise the error in the measurement of volume of water in the measuring cylinder?
Answer:
We can use the measuring cylinder having a scale of less least count.

Question 14.
What change in volume of water observe when water is heated uniformly from 0°C to 100°C?
Answer:
The volume of water decreases upto 4°C and then further increases.

Question 15.
Which water has the lesser density River water or Sea water?
Answer:
River water.

NCERT Lab Manual Questions

Question 1.
Can you determine the density of a porous solid by using a spring balance and a measuring cylinder? Give reasons in support of your answer.
Answer:
No, we cannot determine the density of a porous solid by using a spring balance and a measuring cylinder because

  1. the porous solid have a void space in the form of pores in it.
  2. It will absorb some water.
  3. absorption of water by the porous solid may affect the
    • change in its weight and
    • volume of water displaced by it.

Question 2.
How does the presence of an air bubble in the liquid taken in the measuring cylinder affect the volume of the solid?
Answer:
The presence of air bubble inside the water taken in the measuring cylinder increases the volume of water in the cylinder. This may affect the apparent change in volume of the solid.

Question 3.
Density of a sealing wax is 1.8 g/cm3, express it in kg/m3.
Answer:
Density of a sealing wax is 1.8 g/cm3
1.8 g/cm3 = \(\frac { { 1.8 }\times { 10 }^{ -3 } }{ ({ 10 }^{ -2 })^{ 3 } }\) kg/m3 = 1.8 x 103 kg/m3

Question 4.
A metal cylinder is melted and the whole mass is cast in the shape of a cube. What happens to its density? Give reasons.
Answer:
In both the cases, (i) mass and (ii) volume of water displaced by the metallic cylinder and cube remain same. So mass per unit volume does not change. Hence the density of a cube will be equal to the density of the cylinder.

Question 5.
At which temperature is the density of water maximum?
Answer:
Density of water is maximum at 4°C because water when cooled contracts upto 4°C and it expands when cooled further below 4°C. (The density of water at 4°C = 1000 kg/m3)

Practical Based Questions

Multiple Choice Questions/VSA (1 Mark)

Question 1.
The density of which of the following cannot be measured accurately using a spring balance and a measuring cylinder? [CBSE 2010]
(a) A ball filled with a liquid having a leakage
(b) A block of ice at 0 °C
(c) A small porous solid
(d) All of these

Question 2.
You are given a sphere of radius 2 cm. If you are asked to select a best suited spring balance to determine its weight, then out of the following which one would you prefer? The sphere is made of an alloy of density 7 x 103 kg m-3. [CBSE 2011, 2010, NCT 2007]
(а) Range 0 – 1000 gwt, Least count 5 g wt
(b) Range 0 – 500 gwt, Least count 2.5 gwt
(c) Range 0 – 250 gwt, Least count 2.5 gwt
(d) Range 0 – 100 gwt, Least count 1 gwt

Question 3.
The water level in a measuring cylinder, before and after immersing a metal cube in it, is shown in the figure. The volume of the metal cube is: [CBSE 2010]
CBSE Class 9 Science Practical Skills - Density of Solid 5
(a) 24 cm3
(b) 22 cm3
(c) 20 cm3
(d) 18 cm3

Question 4.
Four measuring cylinders with least count 2.5 ml, 1.0 ml and 0.5 ml and 0.2 ml are available. Which one should be preferred for finding the density of a solid accurately? The one having least count:
[CBSE 2011, 10]
(a) 2.5 ml
(b) 1.0 ml
(c) 0.5 ml
(d) 0.2 ml

Question 5.
Three students A, B and C noted the water level reading in the measuring cylinder, as shown in figure. The correct way of taking reading is of: [CBSE 2010]
CBSE Class 9 Science Practical Skills - Density of Solid 6
(a) A and C
(b) Only B
(c) Only C
(d) A and B

Question 6.
In a spring balance the space between 0 and 25 g marks is divided into 10 equal parts. The least count of spring balance is: [CBSE 2010]
(a) 2.5 g wt
(b) 25 g wt
(c) 0.25 g wt
(d) 15 g wt

Question 7.
The least count of the spring balance shown in the diagram is: [CBSE 2010]
CBSE Class 9 Science Practical Skills - Density of Solid 7
(a) 5 g
(b) 2 g
(c) 1 g
(d) 0.5 g

Question 8.
In the following figure the zero error is: [CBSE 2010]
CBSE Class 9 Science Practical Skills - Density of Solid 8
(a) 2 g wt
(b) -2 g wt
(c) 5 g wt
(d) -5 g wt

Question 9.
If we want to determine the volume of a solid by immersing it in water, the solid should be
[CBSE 2010]
(a) lighter than water.
(b) heavier than water.
(c) insoluble in water.
(d) heavier than water and insoluble

Question 10.
The correct way of reading the liquid level is shown in [CBSE 2012, 2011]
CBSE Class 9 Science Practical Skills - Density of Solid 9
(a) Figure A
(b) Figure B
(c) Figure C
(d) Figure D

Question 11.
A given solid is weighed in air using a spring balance. It is then weighed by immersing it fully, in each of the three different vessels A, B and C as shown. The weight of solid would be [CBSE 2012]
CBSE Class 9 Science Practical Skills - Density of Solid 10
(a) more in vessel C
(b) more in vessel B
(c) more in vessel A
(d) equal in all the three vessels.

Question 12.
The level of water in a measuring cylinder before and after a solid of 8 g mass is fully immersed into it as shown.
CBSE Class 9 Science Practical Skills - Density of Solid 11
The density of the given solid is: [CBSE 2012]
(a) 4 g/cm3
(b) 2 g/cm3
(c) 3 g/cm3
(d) None of these

Question 13.
The least count of the spring balance and the measuring cylinder respectively are: [NCT 2007]
CBSE Class 9 Science Practical Skills - Density of Solid 12
(a) 1 g wt; 1 ml
(b) 1 g wt; 2 ml
(c) 2 g wt; 1 ml
(d) 2 g wt; 2 ml

Question 14.
A student performing the experiment ‘To determine the density of solid (denser than water), by using spring balance and measuring cylinder’. During the experiment, he observed that a few air bubbles are sticking to the solid when immersed in water. The presence of air bubbles will lead to
(a) no change in density
(b) increase in density
(c) decrease in density
(d) none of the above

Question 15.
A spring balance reads 10 kg when a bucket of water is suspended from it. An iron piece having some mass is suspended by another string and immersed in the bucket with half of its volume. The reading of balance will
(a) decrease
(b) increase
(c) remain the same
(d) another spring balance needed

Question 16.
While determining the density of a copper piece using a spring balance and a measuring cylinder, seema carried out the following procedure:
(i) Noted the water level in the measuring cylinder without the copper piece.
(ii) Immersed copper piece in water.
(iii) Noted the water level after immersing copper in the measuring cylinder.
(iv) Removed the copper piece from the water and immediately weighted it using a spring balance.
The wrong step in the procedure is:
(a) (i)
(b) (ii)
(c) (iii)
(d) (iv)

Question 17.
CBSE Class 9 Science Practical Skills - Density of Solid 13
Four measuring cylinders with different least counts are shown in figures A, B, C and D respectively. The most suitable cylinder for determining the volume of a cube of side 1 cm is
(a) A
(b) B
(c) C
(d) D

Question 18.
While determining the density of a solid, a student is provided with four different combinations.
Measuring cylinder

S. No. Range Least count
1. 0 – 100 ml 1 ml
2. 0 – 200 ml 5 ml
3. 0 – 100 ml 2 ml
4. 0 – 200 ml 2 ml

 Spring balance

S. No. Range Least count
1. 0 – 100 g wt 1 g wt
2. 0 – 200 g wt 5 g wt
3. 0 – 100 g wt 2 g wt
4. 0 – 200 g wt 2 g wt

The student should prefer to choose combination
(a) 1-1
(b) 2-2
(c) 3-3
(d) 4-4

Question 19.
A student notes down the observations in two spring balances and the measuring cylinder shown in the figure. From the given observations, the volume of the solid is
CBSE Class 9 Science Practical Skills - Density of Solid 14
(a) 64 cc
(b) 36 cc
(c) 28 cc
(d) 100 cc

Answers

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

Short Answer Questions (2 Marks)

Question 1.
Define relative density of a substance. Relative density of silver is 10.8. The density of water is 1000 kgm-3. What is the density of silver in SI units?
Answer:
Relative density is defined as the ratio of density of a substance to the density of water. Therefore,
Relative density = \(\frac { Density\quad ofa\quad substance }{ Density\quad of\quad water }\)
Density of silver = Relative density of silver x Density of water
= 10.8 x 1000 = 1.08 x 104 kgm-3.

Question 2.
Differentiate between density and relative density.
Answer:

Density Relative density
1. It is equal to the mass per unit volume of a body. 1. It is the ratio of density of a body to the density of water.
2. Its unit is SI kgm-3. 2. It has no unit as it is the ratio of same quantity.

 Question 3.
Arpita was given a solid sphere of metal of mass 100 g. She immersed it in a measuring cylinder and found that the level of water was raised by 30 mL. Calculate the density of metal as measured by her.
Answer:
Mass of solid = 100 g
Volume of solid=30 mL
Density of solid = \(\frac { Mass\quad of\quad Solid }{ Volume\quad of\quad Solid } =\frac { M }{ V } =\frac { 100 }{ 30 }\) = 3.33 gmL-1

Question 4.
In the experiment, to determine the density of a given solid (denser than water) by using a spring balance and a measuring cylinder, a student made the following observations.

  • Mass of solid = 115 g
  • Initial reading of water level in measuring cylinder = 45 mL
  • Final reading of water level in measuring cylinder = 69 mL

On the basis of these observations, what should be the density of a given solid if the spring balance showed a reading of -5 g before suspending the solid?
Answer:
Corrected mass of the solid = 115 – (-5) = 120 g
Density of solid = \(\frac { Mass\quad of\quad Solid }{ Volume\quad of\quad Solid } =\frac { M }{ V } =\frac { 120\quad g }{ \left( 69-45 \right) mL } =\frac { 120\quad g }{ 24\quad mL }\) =5 gmL-1

Question 5.
The density of aluminium is 2700 kgm-3. What does it mean? Calculate the density of aluminium 1 in CGS system.
Answer:
It means that 1 m3 volume of aluminium has a mass of 2700 kg.
Density of aluminium in CGS system
= \(\frac { 2700\times 1000 }{ 100\times 100\times 100 }\)
= 2700 x 10-3
= 2.7 g cm-3

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