CBSE Previous Year Solved Papers Class 12 Computer Science Outside Delhi 2015
Time allowed : 3 hours Maximum Marks: 70
General Instructions :
- There are a total of 26 questions and five sections in the question paper, All questions are compulsory.
- Section A contains question number 1 to 5, Very Short Answer type questions of one mark each.
- Section B contains question number 6 to 10, Short Answer type I questions of two marks each.
- Section C contains question number 11 to 22, Short Answer type II questions of three marks each.
- Section D contains question number 23, Value Based Question of four marks.
- Section E contains question number 24 to 26, Long Answer type questions of five marks each.
- There is no overall choice in the question paper, however, an internal choice is provided in one question of two marks, one question of three marks and all three questions of five marks. An examined is to attempt any one of the questions out of two given in the question paper with the same question number.
Question.1. (a) How is_init () _different from _del () ?
(b) Name the function/method required to
(i) Check if a string contains only alphabets
(ii) Give the total length of the list.
(c) Rewrite the following code in python after removing all syntax error(s). Underline each correction done in the code.
(d) Find and write the output of the following python code :
(e) Find and write the output of the following python code:
(f) What are the possible outcome(s) executed from the following code ? Also specify the maximum and minimum . values that can be assigned to variable COUNT. TEXT=”CBSEONLINE”
Answer : (a) _init is used to initialise newly created object, and receives arguments used to do that while_del_ is used for destructor
Question.2. (a) Illustrate the concept of inheritance with the help of a python code.
(b) What will be the output of the following python code ? Explain the try and except used in the code.
(c) Write a class PHOTO in Python with following specifications:
(d) What is operator overloading with methods ? Illustrate with the help of an example using a python code.
(e) Write a method in python to display the elements of list twice, if it is a number and display the element terminated with if it is not a number.
For example, if the content of list is as follows ;
Question.3. (a) What will be the status of the following list after fourth
pass of bubble sort and fourth pass of selection sort used for arranging the following elements in descending order ?
34, -6, 12, -3, 45, 25
(b) Write a method in python to search for a value in a given list (assuming that the elements in list are in ascending order) with the help of Binary Search method. The method sould return -1, if the value not present else it should return position of the value present in the list.
(c) Write PUSH (Names) and POP(Names) methods in
python to add Names and Remove Names considering them to act as Push and Pop operations of Stack.
(d) Write’ a method in pythons, to find and display the
composite numbers between 2 to N. Pass N as argument to the method.
(e) Evaluate the following post fix notation of expression.
Show status of stack after every operation.
34, 23, +, 4, 5, *, –
Question.4. (a) Differentiate between the following:
(i) f = open (‘diary.txt’,’a’)
(ii) f = open (‘diary.text1 , ‘w’)
(b) Write a method in python to read the content from a text file story.txt line by line and display the same on screen.
(c) Consider the following definition of class Student. Write a method in python to Write the content in a pickled file student.dat.
Question.5. (a) Observe the following table carefully and write the names of the most appropriate columns, which can be considered as (i) candidate keys and (ii) primary key :
(b) Consider the following DEPT and EMPLOYEE tables. Write SQL queries for (i) to (iv) and find outputs for SQL queries (v) to (viii).
Note : DOJ refers to date of joining and DOB refers to date of Birth of employees.
(i) To display Eno, Name, Gender from the table EMPLOYEE in ascending order of Eno.
(ii) To display the Name of all the Male employees from the table EMPLOYEE.
(iii) To display the Eno and Name of those employees from the table EMPLOYEE who are born between T987-01-01′ and’1991-12-01′.
(iv) To count and display FEMALE employees who have joined after ‘1986-01-01’.
(v) SELECT COUNT (*), DCODE FROM EMPLOYEE GROUP BY DCODE HAVING COUNT (*) > 1;
(vi) SELECT DISTINCT DEPARTMENT FROM DEPT;
(vii) SELECT NAME , DEPARTMENT FROM EMPLOYEE E , DEPT D
WHERE E . DCODE=D . DCODE AND ENO< 1003;
(viii) SELECT MAX (DOJ) , MIN (DOB) FROM EMPLOYEE;
Question.6. (a) Verily the following using Boolean Laws :
U’ + V = UV + U’ .V + U.V *’
(b) Draw the Logic Circuit for the following Boolean Expression:
(X’ + Y).Z + W’
(c) Derive a Canonical POS expression for a Boolean function F represented by the following truth table:
(d) Reduce the following Boolean Expression to its simplest form using K-Map :
Question.7.(a) Illustrate the layout for connecting 5 computers in a Bus and a Star topology of Networks.
(b) What kind of data gets stored in cookies and how is it useful ?
(c) Differentiate between packet switching over message switching.
(d) Out of the following, which is the fastest (i) wired and
(ii) wireless medium of communication ?
Infrared, Coaxial Cable, Ethernet Cable, Microwave, Optical Fiber.
(e) What is Trojan Horse ?
(f) Out of the following, which all comes under cyber crime ?
(i) Stealing away a brand new hard disk from a showroom.
(ii) Getting in someone’s social networking account without his consent and posting on his behalf.
(iii) Secretly copying data from server of an organization and selling it to the other organization.
(iv) Looking at online activities of a friends blog.
(g) Xcelencia Edu Services Ltd. is an educational organization. It is planning to set up its India campus at Hyderabad with its head office at Delhi. The Hyderabad campus has 4 main buildings – ADMIN, SCIENCE, BUSINESS and ARTS. You as a network expert have to suggest the best network related solutions for their problems raised in (i) to (iv), keeping in mind the distances between the buildings and other given parameters.
(i) Suggest the most appropriate location Of the server
inside the HYDERABAD campus (out of the 4 buildings) to get the best connectivity for maximum number of computers. Justify your answer.
(ii) Suggest and draw the cable layout to efficiently connect various buildings within the HYDERABAD campus for connecting the computers.
(iii) Which hardware device will you suggest to be procured by the company to be installed to protect and control the internet uses within the campus ?
(iv) Which of the following will you suggest to establish the online face-to-face communication between the people in the Admin Office of HYDERABAD campus and DELHI Head Office ?
(ii) Text Chat
(iii) Video Conferencing
(iv) Cable TV
(b) A cookie‘s contents are determined by the specific website that created that cookie. Contents vary from site to site. As a general rule, cookies contain random alphanumeric text characters.
Cookies are intended to help you access a site faster and more efficiently. For example, cookies can store information to help you enter a site without having to login.
Message switching is called a store-and-forward technology because the entire message must be received and stored before being sent on to the next system. Email is a good example of this type of technology (the entire email message is sent to an SMTP server before being relayed to another one).
Packet switching involves the breaking down of the message into smaller units, called packets. These packets are then sent one at a time from the sender to the receiver. The packets (or smaller pieces) may be received in any order and are then reassembled back into the original message.
(d) fastest wired medium of communication is Optical Fiber, fastest wireless medium of communication is Microwave
(e) In computers, a Trojan horse is a program in which . malicious or harmful code is contained inside apparently
harmless programming or data in such a way that it can get control and do its chosen form of damage, such as ruining the file allocation table on your hard disk. In one celebrated case, a Trojan horse was a program that was supposed to find and destroy computer viruses. A Trojan horse may be widely redistributed as part of a computer virus.
(f) Out of the following, following comes under cyber crime Getting in someone’s social networking account without his consent and posting pictures on his behalf to Secretly copying files from server of a call center and selling it to the other organization.
(i) The most appropriate location of the server inside the HYDERABAD campus (out of the 4 buildings), is ADMIN block because this block have maximum number of , computers.
(iii) firewall device will be procured by the company to be installed to protect and control the internet uses within the campus.
(iv) Video Conferencing will be best to establish the online face-to-face communication between the people in the Admin Office of HYDERABAD campus and DELHI Head Office.