CBSE SAMPLE PAPER 1 COMPUTER SCIENCE

Class XII

Computer Science (083)

Sample Paper I


Maximum Marks: 70                                                                                                                                                                                                                                                                                                                                    Time Allowed:3 Hours

General Instructions :

(i) Please check this question paper, which contains 35 questions.

(ii) The paper is divided into 5 Sections - A, B, C, D and E.

(iii)Section A, consists of 18 questions (1 to 18). Each question carries  1 mark.

(iv)Section B consists of 7 questions (19 to 25). Each question carries 2 marks.

(v)Section C consists of 5 questions (26 to 30). Each question carries 3 marks.

(vi)Section D consists of 2 questions (31 to 32). Each question Carries 4 marks.

(vii) Section E, consists of 3 questions (33 to 35). Each question carries 5 marks.

(viii) All programming questions will be answered using Python Language only.

SECTION - A                  



1. State True or False.                                                                              

                  "Python is an interpreted language."

 2. Which of the following are keywords in Python?

a)  break

b)  check

c) range


d) while


3. Which of the following is not a sequential datatype in Python?

(a) Dictionary

(b) String

(c) List

(d) Tuple

4. In Python, what does the len( ) function primarily measure for a string? 

A. Number of characters

B. Memory usage

C. Byte size

D. String length

5. Fill in the blank :

            _________ statement of SQL is used to insert new records in a table.

(a) ALTER

(b) UPDATE

(c) INSERT

(d) CREATE

6. Write the names of the immutable data objects from the following :

(a) List 

(b) Tuple 

(c) String

(d) Dictionary

7. Which of the following is NOT a Python exception?  

(a) ValueError

(b) IOError

(c) ModuleError

(d) IndexError

8. The correct syntax of the tell( ) methods  is :

(a) tell.file_object( )

(b) file_object.tell( )

(c) tell.file_object(1 )

(d) file_object.tell(1)

9.  Which statement(s) would give an error after executing the following code?

            S="Happy"                        # Statement 1

          print(S*2)                         # Statement 2

          S+="Independence"          # Statement 3

          S.append("Day")               # Statement 4

          print(S).                           # Statement 5

(a) Statement 2 

(b) Statement 3

(c) Statement 4 

(d) Statements 3 and 4

10. How can we retrieve all the columns from the' Student' table?                                                                                                       

(a) SELECT * FROM Student

(b) RETRIEVE ALL FROM Student

(c) SELECT ALL FROM Student

(d) GET * FROM Student

11. Which of the following is an invalid variable name in Python? 

(a) _name

(b) name1

(c) 1name

(d) name_

12. Which symbol is used in Python to make a single-line comment? 

(a) //

(b) #

(c) *

(d) /* */

13. In packet switching, data is broken down into smaller units called _________.

(a) Packets

(b) Segments

(c) Fragments

(d) Blocks

14. Which of the following is NOT a Python data type? 

(a) tuple

(b) listicle

(c) dict

(d) set

15. What does the term 'relation' refer to in a relational database? 

(a) Function

(b) Table

(c) Database

(d) Relation between tables

16. Which of the following is the correct file mode to append to a file in Python? 

(a) 'r'

(b) 'a'

(c) 'x'

(d) 'w'

Q. 17 and 18 are ASSERTION (A) AND REASONING (R) based questions. Mark the correct choice as: 

(a) Both (A) and (R) are true and (R) is the correct explanation for (A).

(b) Both (A) and (R) are true and (R) is not the correct explanation for(A).

(c) (A) is true but (R) is false.

(d) (A) is false but (R) is true.

17.

Assertion (A): In Python, lists are mutable.

Reason (R): Mutable means the content of the variable can be changed after declaring it.

18.

 Assertion (A): In SQL, the 'JOIN' command combines rows from two or more tables.

Reason (R): It's based on a related column between them.


                                                              SECTION B                                            

19. Write any two differences between Fiber-optic cable and Coaxial cable.

                                                                                                              OR

(b) Write one advantage and one disadvantage of wired over wireless Communication.


20. (a)Given is a Python string declaration: 

            NAME = "Learning Python is Fun"

        Write the output of : print(NAME[-5:-10:-1])

     (b)  If x = (10, 20, (30, 40), [50, 60])

        what will be the result of x[3][0]?

21.  Consider the Python code :

      data = {

                   " Mike " : [88, 92, 79],

                   " Lucy " : [91, 87, 90] ,

                   " John " : [85, 86, 88]

                  }

     This dictionary represents the marks of three students in three subjects. Write a Python function to calculate the average marks of each student.

22. Explain the concept of  Unique Key in Relational Database Management Systems. Also, provide an example illustrating its use.

23. (A) Write the full form of  : 

         i)PPP

         ii)TCP/ IP

       (B) What do you understand by domain names? Why these are necessary?

24. Consider the table Sales given below:

Order_ID  Product  Quantity  Price Date  
1 Laptop  550000 2024-01-15
2 Mouse 50500 2024-02-18
3 Keyboard301500 2024-03-10 
4Monitor 10100002024-04-05
5Laptop3550002024-05-25


Based on the table, write SQL queries for the following:

         (i) Calculate the total quantity of all products sold.

        (ii) Find the average price of products sold.

        (iii) Determine the maximum price for all products.

25. (A) Ravi, a Python programmer, is working on a project where he wants to write a function to count the number of even and odd values in the list. He has written the following code but his code is having errors. Rewrite the correct code and underline the corrections made. 

define EOCOUNT(L):

        even_no=odd_no=0

    for i in range(0,len(L))

       if L[i]%2=0:

      even_no+=1

   Else:

     odd_no+=1

print(even_no, odd_no)

                                                                                                                                                    


                                                           SECTION C                                                                              

26. Write the outputs of the SQL queries (i) to (iii) based on the relations CUSTOMER and TRANSACTION given below :

Table- CUSTOMER 

ACNONAME GENDER BALANCE
C1RISHABHM15000
C2AAKASHM12500
C3INDIRAF9750
C4TUSHARM14600
C5ANKITAF22000

Table - TRANSACTION

 ACNOTDATEAMOUNTTYPE
 C12020-07-211000DEBIT
 C52019-12-311500CREDIT
C32020-01-012000CREDIT

 

( i )   SELECT MAX (BALANCE), MIN (BALANCE) FROM CUSTOMER

        WHERE GENDER = ' M ' ;


( ii )  SELECT SUM (AMOUNT), TYPE FROM TRANSACTION GROUP BY TYPE ;


( iii ) SELECT NAME, TDATE, AMOUNT

        FROM CUSTOMER C, TRANSACTION T

        WHERE C.ACNO = T .ACNO AND TYPE = 'CREDIT' ;


27. ( A )  Create a Python function named WordFrequency( ) which takes the contents from a file 'WORDS.TXT' and displays the frequency of each word.

 For example,  if the file contains:

           apple apple banana apple cherry cherry

The function should display:

             apple: 3

             banana: 1

             cherry: 2

OR

      ( B)  Develop a Python function called EvenLines( ) that reads from a file 'LINES.TXT' and only displays the even-numbered lines. 

      For example, the file content:

This is line one.

This is line two.

This is line three.

This is line four.

The output should be:

This is line two.

This is line four.

28. Write the output of any three SQL queries (i) to (iv) based on the tables COMPANY and CUSTOMER given below :

Table: COMPANY

CIDC NAMECITYPRODUCT NAME
111SONYDELHITV
222NOKIAMUMBAIMOBILE
333ONIDADELHITV
444SONYMUMBAIMOBILE
555BLACKBERRYCHENNAIMOBILE
666DELLDELHILAPTOP


Table: CUSTOMER

CUSTIDCIDNAMEPRICEQTY
C01222ROHIT SHARMA7000020
C02666DEEPIKA KUMARI5000010
С03111MOHAN KUMAR300005
CO4555RADHA MOHAN3000011


i)  SELECT PRODUCTNAME, 

    COUNT(*)FROM COMPANY GROUP BY

    PRODUCTNAME HAVING COUNT(*)> 2;

(ii) SELECT NAME, PRICE, 

     PRODUCTNAME FROM COMPANY C,

     CUSTOMER CT WHERE C.CID = CU.CID AND C_NAME = 'SONY';

(iii) SELECT DISTINCT CITY FROM COMPANY;

(iv) SELECT * FROM COMPANY WHERE C_NAME LIKE '%ON%';

29.  Write a function HalveEven( ) in Python, which accepts a list L of numbers. After that, it halves all even numbers.

Example:

If the Sample Input data of the list is: L = [10, 12, 15, 28, 33]

 Output will be: L = [5, 6, 15, 14, 33]

30. A list contains the following record of customers:  (Customer_ name, Room Type]

Write the following user-defined functions to perform given operations on the stack named 'Hotel' :

(i) Push_Cust ( ) - To Push customers' names of those customers who are staying in the 'Delux' Room Type.

(ii) Pop_Cust ( ) - To Pop the names of customers from the stack and display them. Also, display "Underflow" when there are no customers in the stack.

For example :

If the lists with customer details are as follows :

["Siddarth", "Delux"] ["Rahul", "Standard"]

["Jerry", "Delux"]

The stack should contain

Jerry

Siddharth

The output should be:

Jerry

Siddharth

Underflow

                                                          SECTION D                                                              

31.  A startup has hired Ms. Serena to manage their team of developers. She's required to keep a record of all the developers with their skills and experience.

DEV_ID DEV_NAMESKILL   EXPERIENCE (in years)TEAM 
 D001JohnPython  3 Web 
 D002  Alice| JavaScript5Frontend 
D003 Bob   SQL2Backend 
D004 Carol  Java 4Mobile 


Based on the data given above, answer the following questions:

(i) Identify the columns that can be considered as Candidate keys.         

(ii) Write the SQL commands to:

    (a) Add a new developer with relevant details.                                    

    (b) Update the experience of a developer by 1 year.

(iii) Write the SQL statements to:

   (a) Add a constraint PRIMARY KEY to the column DEV_ID.

   (b) Remove the record of a developer by DEV_ID.

32. Atharva is a programmer, who has recently been given a task to write a Python code to perform the following binary file operation with the help of a user-defined function/module :

Copy_new(): to create a binary file new_items.dat and write all the item details stored in the binary file, items.dat, except for the item whose item_id is 101. The data is stored in the following format: { item_id: [item_name, amount]}

import ___________                                   # Statement 1

def Copy_new():

f1=_____________                                   # Statement 2

f2=_____________                                   # Statement 3

item_id=int(input("Enter the item id"))

item_detail=___________                         # Statement 4

for key in item_detail:

if _______________:                               # Statement 5

pickle.___________                                 # Statement 6

f1.close()

f2.close()

He has succeeded in writing partial code and has missed out certain statements. Therefore, as a Python expert, help him to complete the code based on the given requirements :

(i) Which module should be imported into the program? (Statement 1) 

(ii) Write the correct statement required to open the binary file "items.dat". (Statement 2) 

(iii)  a) Which statement should Atharva fill in Statement 3 to open the binary file "new_items.dat" and in Statement 4 to read all the details from the binary file "items.dat"? 

                                             OR (Option for part iii only)

(iii)b) What should Atharva write in Statement 5 to apply the given condition and in Statement 6 to write data in the binary file "new_items.dat"

                                                                 SECTION E

33. XYZ Techcorp is establishing a new campus in Bengaluru with its head office in Mumbai. The Bengaluru campus has five buildings:

Bengaluru Campus Layout

Block to Block distances (in Mtrs.)

From  To Distance
ADMIN HR 30 m
ADMINDEVELOPMENT 80 m
ADMINSALES  60 m
HR  DEVELOPMENT 50 m
HR  SALES  40 m
DEVELOPMENT SALES  70 m
DEVELOPMENT  IT 90 m
SALES   IT 50 m


The number of computers in each of the blocks/Centers is as follows:

BlockComputers
ADMIN150  
HR70
DEVELOPMENT 100 
SALES  40 
IT80 
MUMBAI HEAD OFFICE30 

Based on the above-given information, answer the following questions. 

(a) Suggest and draw the cable layout to efficiently connect various blocks of buildings within the BENGALURU campus for connecting digital devices.

(b) Which network device will be used to connect computers in each block to form a local area network?

(c) Which block in the Bengaluru Campus should be made the server? Justify your answer.

(d) Which fast and very effective wireless transmission medium should preferably be used to connect the head office in MUMBAI with the campus in BENGALURU?

(e) Is there a requirement for a repeater in the given cable layout? Why/Why not?

34. (A ) Write a point of difference between append (a) and write (w)  modes in a text file.   

 (B). Write a program in Python that defines and calls the following  user-defined functions :

          (i) Add_Teacher( ): It accepts the values from the user and the Inserts record consists of a list with field elements as T_id, Tname and design to store teacher ID, teacher name and designation respectively.

          (ii) Search_Teacher( ): To display the records of all the PGT(designation) teachers.

                                                         OR

(A ) Write one point of difference between the seek( ) and tell( )  functions in file handling.

(B) Write a program in Python that defines and calls the following user-defined functions : 

(i) Add_Device(): The function accepts and adds records of the consists of a list with field elements as P_id, P_name and Price to store peripheral device ID, device name, and price respectively.

(ii) Count_Device(): To count and display the number of peripheral devices, whose price is less than < 1000.

35. (A) Predict the output of the following code:

x = "HELLO"

for char in x:

    if char == 'E':

        continue

    print(char, end='')

(a) HELLO 

(b) HLL 

(c) HLLO 

(d) HLO

(B) The provided code updates the products table to set the price of the item with P_code P504 to 150.

    import ________ as db_module    # Statement 1

    def update_price():

        db_connection = db_module.connect(host="localhost", user="storeadmin", passwd="________", database="store_db")             # Statement 2

        cursor = db_connection.cursor()

        _______________                 # Statement 3 (Update the price of the product with P_code 'P504')

        _______________                 # Statement 4 (Commit the changes)

        print("Price updated")

  Complete the above statement by filling in the blanks.