Computer Science - Sample Paper Class 12 CBSE Board Exam 2020

The sample paper is one of the best resources for the student to prepare for the exam. These help the student to get a prior experience before they attempt for the final exam also, they will know if they are prepared for the exam completely or not. They can test their knowledge for all these subjects and get confident about the answer. if any discrepancies occur in the written answer, they can focus more on such a question, so that there are no mistakes happening in the final paper. they can also mark themselves for correct and wrong answers.

Structure of CBSE Class 12th Computer Science Model Paper 2020

Computer Science, the paper will be of three hours and a total of 70 marks. All questions are compulsory.

• Question paper is divided into 4 sections A, B, C and D.
• Section A : Unit-1
• Section B : Unit-2
• Section C: Unit-3
• Section D: Unit-4

SECTION-A

Q1     (a) Which of the following is valid arithmetic operator in Python:

                   (i) //           (ii) ?            (iii) <   (iv) and

        

        (b) Write the type of tokens from the following:

                  (i) if             (ii) roll_no

        (c) Name the Python Library modules which need to be imported to                  invoke the following functions:

                        (i) sin()        (ii) randint ()

        (d) Rewrite the following code in python after removing all syntax             error(s). Underline each    correction done in the code.

       

        30=To

        for K in range(0,To)

              IF k%4==0:

             print (K*4)

         Else:

                    print (K+3)

        (e) Find and write the output of the following python                 code:  

            def fun(s):

     k=len(s)

       m=" "

for i in range(0,k):

        if(s[i].isupper()):

    m=m+s[i].lower()

elif s[i].isalpha():

    m=m+s[i].upper()

else:

         m=m+'bb' print(m)

          fun('school2@com')

          (f) Find and write the output of the following python code:

        def Change(P ,Q=30):

        P=P+Q

        Q=P-Q

        print( P,"#",Q)

        return (P)

          R=150

          S=100

          R=Change(R,S)

          print(R,"#",S)

            S=Change(S)

          (g) What possible outputs(s) are expected to be displayed on the screen at                  the time of execution of the program from the following code? Also, specify                 the maximum values that can be assigned to each of the variables                             FROM and TO.

          import random        

          AR=[20,30,40,50,60,70];                           FROM=random.randint(1,3)                     TO=random.randint(2,4)   

     for K in range(FROM,TO+1):

     print (AR[K],end=”#“)

        (i) 10#40#70# (ii) 30#40#50#

            (ii) 50#60#70# (iv) 40#50#70#

Q2.    (a) What do you understand by the term Iteration?

        (b) Which is the correct form of declaration of the dictionary?

                   (i)       Day={1:’monday’,2:’tuesday’,3:’wednesday’}

                   (ii)      Day=(1;’monday’,2;’tuesday’,3;’wednesday’)

                   (iii)     Day=[1:’monday’,2:’tuesday’,3:’wednesday’]

                   (iv)     Day={1’monday’,2’tuesday’,3’wednesday’]

       

        (c) Identify the valid declaration of L:

                 L = [1, 23, ‘hi’, 6].

                    (i) list           (ii) dictionary        (iii) array     (iv) tuple

        (d) Find and write the output of the following python code:

        x = "abcdef" i = "a"

        while i in x:

          print(i, end = " ")

        (e) Find and write the output of the following python code:

        a=10

        def call():

               global a

               a=15

               b=20

               print(a)

          call()

        (f)  What do you understand by the local and global scope of variables? How can you access a global variable inside the function, if the function has a variable with the same name?

        (g) A bar chart is drawn(using pyplot) to represent sales data of various models of cars, for a month. Write appropriate statements in Python to provide labels Month - June and Sale have done to x and y-axis respectively.

          OR

        Give the output from the given python code:

        import matplotlib.pyplot as plt; plt.rcdefaults()

        import numpy as np

        import matplotlib.pyplot as plt

        objects = ('Python', 'C++', 'Java', 'Perl', 'Scala', 'Lisp') y_pos =             np.arange(len(objects))

        performance = [10,8,6,4,2,1]

        plt.bar(y_pos, performance, align='center', alpha=0.5)               plt.xticks(y_pos, objects)

        plt.ylabel('Usage') plt.title('Programming language usage')

        plt.show()

        (h) Write a function in python to count the number of lines in a text file        ‘STORY.TXT’ which is starting with an alphabet ‘A’.

             OR

        Write a method/function DISPLAYWORDS() in python to read lines from a           text file STORY.TXT, and display those words, which are less than 4                   characters.

        (i) Write a Recursive function in python BinarySearch(Arr,l, R, X) to            search the given element X to be searched from the List Arr having R             elements, where l represents lower bound and R represents the                            upper bound.

                                                        OR

        Write a Recursive function recurfactorial(n) in python to calculate and              return the factorial of number n    passed to the parameter.

        (j) Write a function in Python, INSERTQ(Arr, data) and DELETEQ(Arr) for       performing insertion and deletion operations in a Queue. Arr is the list               used for implementing queue and data is the value to be inserted.

                 OR

        Write a function in python, MakePush(Package) and MakePop(Package) to       add a new Package and delete a     Package from a List of Package                   Description, considering them to act as push and pop operations of the                 Stack data structure.

SECTION-B

Q.3   Questions 3 (a) to 3 (c) : Fill in the blanks

        (a) ………………………..is an example of Public cloud.

        (b) ……………………………. is a network of physical objects embedded with      electronics, software, sensors and network connectivity.

        (c) ---------------------- is a device that forwards data packets along with                networks.

         

        (d) ---------------------- describes the maximum data transfer rate of a               network or Internet connection.

        (e) Give the full forms of the following

              (i)      HTTP

             (ii)      FTP

                  (v)      VoIP

                  (vi)     SSH

                  (vi)     SSH

        (f) How many pair of wires are there in twisted pair cable(Ethernet)? What is             the name of the port, which is used to connect Ethernet cable to a                       computer or a laptop?

          (g) Identify the type of cybercrime for the following situations:

              (i)    A person complains that Rs. 4.25 lacs have been fraudulently stolen from his/her account online via some online transactions in two days using NET BANKING.

        

             (ii)   A person complains that his/her debit/credit card is safe with him still, somebody has done shopping/ATM transactions on this card.

               

                 (iii)   A person complaints that somebody has created a fake profile              on  Facebook and defaming his/her character with abusive                       comments and pictures.

        (h) Software Development Company has set up its new center at Raipur for its office and web-based activities. It has 4 blocks of buildings named        Block A, Block B, Block C, Block D.

                                               Number of Computers

                          

Block A	25
Block B	50
Block C	125
Block D	10

                 

                Shortest distances between various Blocks in meters:

                 

Block A to Block B	60m
Block B to Block C	40m
Block C to Block A	30m
Block D to Block C	50m

             (i)       Suggest the most suitable place (i.e. block) to house                   the server of this company with a suitable reason.

             (ii)      Suggest the type of network to connect all the blocks with                                 suitable reason .

           (iii)     The company is planning to link all the blocks through a                    secure and high speed wired medium. Suggest a way to                                     connect all the blocks.

               (iv)     Suggest the most suitable wired medium for efficiently                           connecting each computer installed in every block out of the                    following network cables:

             ● Coaxial Cable

                  ● Ethernet Cable

                            ● Single Pair Telephone Cable.

SECTION-C

Q.4   (a) Which keyword is used to sort the records of a table in descending order?

        (b) Which clause is used to sort the records of a table?

        (c) Which command is used to modify the records of the table?

        (d) Which clause is used to remove the duplicating rows of the table?

        (e) Differentiate between Primary key and Candidate key.

                             OR

              Differentiate between Degree and Cardinality.

        (f) Differentiate between Django GET and POST method.

        (g) Write an output for SQL queries (i) to (iii), which are based on the table:            STUDENT

       

            given below:

         Table : STUDENT

         

Roll No	Name	Class	DOB	Gender	City	Marks
1	Sonam	X	12-06-1995	F	Delhi	551
2	Akash	XII	05-11-1993	M	Agara	480
3	Manish	XI	01-05-1994	M	Mumbai	500
4	Swra	XII	20-03-1995	F	Jhansi	349
5	Sneha	XII	29-03-1993	F	Jaipur	425
6	Deepak	XI	06-06-1994	M	Jamshedpur	300
7	Deepali	X	14-02-1993	F	Mumbai	289
8	Sanjana	X	08-09-1995	F	Delhi	478

         (i)   SELECT COUNT(*), City FROM STUDENT GROUP BY CITY       HAVING COUNT(*)>1;

         (ii)  SELECT MAX(DOB),MIN(DOB) FROM STUDENT;

             (iii)  SELECT NAME, GENDER FROM STUDENT WHERE CITY=” Delhi”;

(h) Write SQL queries for (i) to (iv), which are based on the table: STUDENT has given in question 4(g):

         (i)   To display the records from table student in alphabetical order as per the name of the student.

         (ii)  To display Class, Dob and City whose marks is between 450 and                 551.

        (iii) To display Name, Class and the total number of students              who have secured more than 450 marks, class wise

             (iv)          To increase marks of all students by 20 whose class is “XII”

SECTION-D

Q.5   (a) It is an internet service for sending written messages                   electronically from one computer to another. Write the service name.

        (b) As a citizen of India, What advice you should give to others for e-waste         disposal?

        (c) What can be done to reduce the risk of identity theft? Write any two ways.

        (d)  

          Ravi received a mail from the IRS department ( as shown above). On                      clicking “ Click-Here”, he was taken to a site designed to imitate an                        official- looking website, such as IRS.gov. He uploaded some important                  information on it.

                  Identify and explain the cybercrime being discussed in the above                        scenario.

        (e) Differentiate between open source and open data.

        (f) Enumerate any two disability issues while teaching and using computers