CBSE Sample Papers for Class 12 Computer Science Set 9 with Solutions

Students must start practicing the questions from CBSE Sample Papers for Class 12 Computer Science with Solutions Set 9 are designed as per the revised syllabus.

CBSE Sample Papers for Class 12 Computer Science Set 9 with Solutions

Time: 3 Hours
Maximum Marks: 70

General Instructions

1. This question paper contains 37 questions.
2. All questions are compulsory. However, internal choices have been provided in some questions. Attempt only one of the choices in such questions.
3. The paper is divided into 5 Sections – A, B, C, D and E.
4. Section A consists of 21 questions (1 to 21). Each question carries 1 Mark.
5. Section B consists of 7 questions (22 to 28). Each question carries 2 Marks.
6. Section C consists of 3 questions (29 to 31). Each question carries 3 Marks.
7. Section D consists of 4 questions (32 to 35). Each question carries 4 Marks.
8. Section E consists of 2 questions (36 to 37). Each question carries 5 Marks.
9. All programming questions are to be answered using Python Language only.
10. In the case of MCQ, the text of the correct answer should also be written.

Section A
(21 × 1 = 21)

Question 1.
State True or False.
The update function updates the contents of one dictionary by another.
Answer:
False

Question 2.
Given L=[2,3,4,5,6]. The output of print(L[-2]) is:
(a) 6
(b) Error
(c) 5
(d) 3
Answer:
(c) 5

Question 3.
Which of the following option can be the output for the following code?
import random
List=[‘Delhi’,’Mumbai’,’Chennai’.’Kolkata’]
List.extend([‘Pune’])
List.pop()
print(List.end=’#’)
(a) [‘Delhi’, ‘Mumbai’, ‘Chennai’, ‘Kolkata’]#
(b) [‘Delhi’, ‘Mumbai’, ‘Chennai’, ‘Kolkata’, ‘Pune’]#
(c) [‘Delhi#’, ‘Mumbai#’, ‘Chennai#’, ‘Kolkata#’]
(d) [‘Delhi’, ‘Mumbai’, ‘Chennai’, ‘Kolkata’, ‘Pune#’]
Answer:
(b) [‘Delhi’, ‘Mumbai’, ‘Chennai’, ‘Kolkata’, ‘Pune’]

Question 4.
Given a list Lst=[45,100,20,30,50], What will be the output of Lst[: :]?
(a) [45,100,20,30,50]
(b) [ ]
(c) Error
(d) [45]
Answer:
(a) [45,100,20,30,50]

Question 5.
Find the output of the following code.
count = 1
def doThis():
global count
for i in (1,2,3):
count += 1
doThis()
print (count)
(a) 3
(b) 4
(c) 2
(d) 0
Answer:
(b) 4

Question 6.
What will be the output of the following code?
tup1 = (1,2,[1,2],3)
tup1[2][1]=3.14
print(tup1)
(a) (1,2,[3.14,2],3)
(b) (1,2,[1,3.14],3)
(c) (1,2,[1,2],3.14)
(d) Error Message
Answer:
(b) (1,2,[1,3.14],3)

Question 7.
Find the output of the following program:
def calcresult():
i=9
while i,>1:
if (i%2 ==0):
x = i%2
i = i – 1
else:
i = i – 2
x = i
print (x**2)
calcresult()
Answer:
Output:
49
25
9
1

Question 8.
Which of the following is an incorrect logical operator in Python?
(a) NOT
(b) IN
(c) OR
(d) AND
Answer:
(b) IN

Question 9.
Identify the output of the following Python statements:
D={}
T=(“ZEESHAN”,”NISHANT”, “GURMEET”,”LISA”)
for i in range (1, 5):
D[i]=T[i-1]
print (D)
(a) {“ZEESHAN”,”NISHANT”,”GURMEET”,”LISA”}
(b) “ZEESHAN”,”NISHANT”,”GURMEET”,”4:”LI SA”)
(c) {[1,”ZEESHAN”],[2,”NISHANT”,[3,”GURMEET “,4;”LISA”)}
(d) [1:”ZEESHAN”,2:”NISHANT”,3:”GURMEET”,4:”LISA”}
Answer:
(d) (1:”ZEESHAN”,2:”NISHANT”,3:”GURMEET”,4 :”LISA”}

Question 10.
Write the missing statement to add the data record to the binary file.
import pickle
f=open(“sport.dat”,”a”)
srec=[“S01”,“Cricket”,11,“SA”]
pickle.___________ #missing blank to write the record.
f.close()
Answer:
dump(srec,f)

Question 11.
State True or False:
TypeError exception is raised when a generated error does not fall into any category.
Answer:
False

Question 12.
What will be the output for the following Python statements?
D= (“AMIT”:90. “RESHMA”:96, “SUKHBIR”:92, “J0HN”:95)
print(“JOHN” in D, 90 in D, sep = “#”)
(a) True#False
(b) True#True
(c) False#True
(d) False#False
Answer:
(a) True#False

Question 13.
Which SQL command allows you to change the data in an existing table?
Answer:
UPDATE

Question 14.
What will the following query do?
Alter table School modify Sname varchar(40);
(a) Adds a new column Sname to the table.
(b) Modifies the table to change width of sname column to varchar(40).
(c) Changes name of the column Schname to Sname
(d) Removes the column Sname.
Answer:
(b) Modifies the table to change width of sname column to varchar(40).

Question 15.
Which of the following functions searches for a string inside another in sql.
(a) searchstr()
(b) find()
(c) getstr()
(d) instr()
Answer:
(d) instr()

Question 16.
The ___________ clause can be used in cases to match records for which partial information exists.
(a) like
(b) get
(c) search
(d) values
Answer:
(a) like

Question 17.
Which of the following would you use to have an audio visual chat with an expert sitting for away to fix technical issues?
(a) E-mail
(b) VoIP
(c) FTP
(d) SMTP
Answer:
(b) VoIP

Question 18.
Which transmission media is commonly used in transporting multi-channel television signals in cities?
(a) Optical Fibre
(b) Co-axial cable
(c) Ethernet cable
(d) None of these
Answer:
(b) Co-axial cable

Question 19.
Which network protocol ensures reliable data transmission by establishing a connection and verifying the delivery of data packets?
Answer:
TCP (Transmission Control Protocol)

Directions (Q. 20 and 21) are Assertion(A) and Reason(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

Question 20.
Assertion (A): A function that is neither built-in nor modular must be defined.
Reason (R): The code of built-in and modular functions is available for the Python compiler, but if the function is not defined anywhere the compiler cannot get the code.
Answer:
(a) Both A and R are true and R is the correct explanation for A.

Question 21.
Assertion (A): The cross-join of two tables produces the maximum number of record outputs.
Reason (R): In cross join each record of one table is matched only once with the matching foreign key record of other tables.
Answer:
(c) A is True but R is False.

Section B
(7 × 2 = 14)

Question 22.
Write the method to perform the following.
(A) Delete a given element from the list.
(B) Get all the keys in a dictionary.
Answer:
(A) remove()
(B) keys()

Question 23.
Write and explain any two dictionary functions.
Answer:
dict(): Can be used to create a new dictionary.
update(): Updates the contents of a dictionary by another dictionary.

Question 24.
Given: l1 = [23, 45, 19, 77, 10, 22]
(i) (a) l1.sort()
Or
(b) max(l1)
(ii) Find error in definition of the function given.
(a) def finderrors(x=20,y)
print(x+y*2)
Or
(b) define newfunc():
ret(10//2 + 10%3)
Answer:
(i) (a) [10, 19, 22, 23, 45, 77]
Or
(b) 77
(ii) (a) Error 1: default parameters must be assigned from right to left
Error 2: Function definition is missing “:”
Correction:
def finderrors(x=20,y=10):
print(x+y*2)
Or
(b) Function to be defined with keyword “def”, values can be returned using the return keyword.
Correction:
def newfunc():
return (10//2 + 10%3)

Question 25.
After executing, what are the possible outcome(s) from the following code? Also, specify the maximum and minimum values that can be assigned to variable NUM.
NAV = [“LEFT”, “FRONT”,”RIGHT”,”BACK”]:
NUM = random, randint(1, 3)
NAVG = ” ”
for C in range (NUM.1, -1):
NAVG = NAVG+NAV[C]
print (NAVG)
(i) BACKRIGHT
(ii) BACKRIGHTFRONT
(iii) BACK
(iv) LEFTFRONTRIGHT
Answer:
Output: only (iv) is not possible.
(i), (ii) and (iii) are possible
Maximum value of NUM = 3
Minimum value of NUM = 1.

Question 26.
What are constraints? Which constraint can be used to create a link between two tables by making one of the columns as foreign key?
Answer:
Constraints are checks or conditions given on fields of a table to restrict entry of invalid data.
Example: Unique, NOT NULL
The Foreign key constraint can be used to create a link between two tables by assigning one of the columns as foreign key in a table.

Question 27.
(i) (a) A table, ITEM has been created in a database with the following fields ITEMCODE, ITEMNAME, QTY, PRICE
Give the SQL command to add a new field, DISCOUNT (of type Integer) to the ITEM table.
Or
(b) Categorize following commands into DDL and DML commands?
INSERT INTO, DROP TABLE, ALTER TABLE, UPDATE…SET
(ii) (a) Charu has to create a database named MYEARTH in MySQL. Write the SQL command to do so.
Or
(b) Now she wants to open it and work in it. Which command will open the database?
Answer:
I. (a) Alter table ITEM Add discount integer;
Or
(b) DDL means ‘DataDefinition Language’. It is used to create and modify the structure of database objects in SQL.
So, DDL commands are DROP TABLE, ALTER TABLE.
DML is ‘Data Manipulation Language’ which is used to manipulate data itself.
So, DML commands are INSERT INTO, UPDATE…SET.
II. (a) Create database MYEARTH;
Or
(b) Use MYEARTH

Question 28.
(a) Expand the following terms:
WAN, VoIP
Or
(b) Two people, one who knows only English and other who knows only Chinese are talking to each other. Can we call this communication?
Answer:
(a) WAN – Wide Area Network
VoIP – Voice over Internet Protocol
Or
(b) No, because only a meaningful exchange of information between two living beings is called communication.

Section C
(3 × 3 = 9)

Question 29.
Write a Python function find_shortest_word() that reads a text file named textfile.txt and finds the shortest word in the file. The function should display the shortest word found. If there are multiple words with the same minimum length, it should return the first one encountered.
e.g. Reading a book is a good way to spend time.
Output should be: a
Or
Write a function countVowels() in Python that reads each character of a text file TEXT.TXT and counts and displays the occurrence of vowels (a, e, i, o, u) including both uppercase and lowercase vowels.
The content of TEXT.TXT is
This is a simple text file to demonstrate vowel counting.
The quick brown fox jumps over the lazy dog.
Output should be: A: 3; E: 8; I: 5; O: 7; U: 2
Answer:
def find_shortest_word():
with open(‘textfile.txt’, ‘ r’) as file:
content = file.read()
words = content.split()
shortest_word = min(words, key=len)
print(f”Shortest word: {shortest_word}”)
Or
def countVowels():
vowels = ‘aeiou’
counts = {v: 0 for v in vowels}
with open(‘TEXT.TXT’, ‘r’) as file:
content = file.read()
for char in content:
if char.lower() in counts:
counts[char.lower()] += 1
for vowel, count in counts.items():
print(f”{vowel .upper()}: {count}”, end=”; “)

Question 30.
(A) John is assigned to define a stack that would store the characters of a string and reverse the string and display. He has to define the following functions for the purpose:
(a) pushstack(stack,character): To push the character parameter into the stack.
(b) popstack(stack): To check the stack emptiness and pop elements from the stack if it is not empty.
(c) isempty(stack): To check and return whether the stack is empty or not.
Or
(B) Write a Python program to input numbers and push them to stack, if the number is divisible by 3 or 5.
Define functions as follows:
(i) push3_5(n): To push the numbers to stack.
(ii) pop3_5(): To pop an element from the stack.
Answer:
(A) def pushstack(stack, ch):
stack.append(ch)
return
def popstack(stack):
if isempty(stack):
return
else:
while not isempty(stack):
print(stack.pop(), end=’ ‘)
return
def isempty(stack):
return len(stack) == 0
#————-main————–
stk = []
str_input = input(“Enter a string: “)
for ch in str_input:
pushstack(stk, ch)
print(“\n———-Reverse———–“)
popstack(stk)
Or
(B) stack3_5 = [ ]
def push3_5(n):
num = int(n) # Convert input string to integer
if num % 3 == 0 or num % 5 == 0:
stack3_5.append(num)
def pop3_5():
if not stack3_5:
print(“Stack empty”)
else:
stack3_5.pop()
ans = ‘y’
while ans == ‘y’:
ch = int(input(“1. Push number\n2. Pop number\nEnter your choice: “))
if ch == 1:
num_input = input(“Enter a number: “)
push3_5(num_input)
elif ch == 2:
pop3_5()
ans = input (“Continue (y/n): “)

Question 31.
Consider the following table Employees given below.

(A) (i) Create the Employees table with the specified columns and constraints.
(ii) Write a query to select all employees who are older than 30 years.
(iii) Write a query to update the salary of employees in the ‘HR’ department by 10%.
Or
(B) (i) Write a query to delete employees who are in the ‘Sales’ department and are younger than 25 years.
(ii) Display name, age and department of employees whose department name ends with “S”.
(iii) Increase salary of “Accts” and “Pers” department employees by 2000.
Answer:
(A) (i) Create table Employees (EmpID INT PRIMARY KEY, Name VARCHAR(50), Age INT, Department VARCHAR(30), Salary DECIMAL(10, 2));
(ii) SELECT *FR0M Employees WHERE Age > 30;
(iii) UPDATE Employees SET Salary = Salary * 1.10 WHERE Department = ‘HR’:
Or
(B) (i) DELETE FROM Employees WHERE Department = ‘Sales’ AND Age < 25:
(ii) Select Name,Age, Department from Employees where Department like “S%”;
(iii) UPDATE Employees SET Salary = Salary +2000 where Department IN (“Accts”, “Pers”);

Section D
(2 × 5 = 10)

Question 32.
(A) (i) When is the ImportError exception raised?
(ii) Which error is raised by the following code?
import pickle as p
try:
f=open(“myfile.dat”,”w”)
p.dump([“1,”Sachin”,”Accts”].”a”)
f.close()
except:
print(“Module not found”)
Or
(B) (i) When is ZeroDivisionError exception raised?
(ii) When is the code in else block executed?
Answer:
(A) (i) Import error is raised if the module being imported is not found.
(ii) ImportError
Or
(B) (i) ZeroDivisionError is Raised the code divides a number by a zero denominator.
(ii) No, the finally block is optional and carries code that will execute, irrespective of whether exception occurs or not.

Question 33.
In a census project Smita has been assigned to write a file handling code that would add aadhar details of people and display certain records from the file.’Help Smita in writing a Python program for operating on a CSV file “people.csv” using following functions:
addPeople() To input details of people and add them to a CSV file “people.csv” without removing the previous records. The record structure’s as follows:
AdhrNo Name City Age
The file should store only those people whose age is greater than and equal to 18.
getPeople() To open the file “people.csv” and display records whose name starts with “P”.
Answer:
import csv
def addPeople():
with open(“people.csv”, “a”) as f:
dt = csv.writer(f)
while True:
ano= int(input(“Enter aadhar No:”))
pname = input(“Enter person name:”)
city = input(“Enter city:”)
age = int(input(“Enter age:”))
if age>=18:
dt.writerow([ano, pname, city, age])
print(“Record has been added.”)
else:
print(“Record could not be added.”)
print(“Want to add more record?Type YES!!!”)
ch = input()
ch = ch.upper()
if ch==”YES”:
print(“______________”)
else:
break
def getPeople():
with open(“people.csv”, ‘r’) as file:
reader = csv.reader(file)
far row in reader:
if row[1][0]==’P’
print(row)
file.close()
addPeople()
getPeople()

Question 34.
Consider the tables Hotel and Room given below:

For the tables given above, write SQL commands for the following.
(i) Insert the 1st record.
(ii) Display the details of customers who have arrived after 01-05-2005.
(iii) Display names and room types of customers whose charges are between 2000 and 3000.
(iv) (a) Display names of customers staying in First floor.
Or
(b) Display name, date of arrival, room types of customers arrived in “September”.
Answer:
(i) INSERT INTO Hotel
VALUES(“T1”, “Ritesh”,“R1”.“2016-09-09”,1800);
(ii) SELECT*FR0M Hotel WHERE DtofArrival > “2005-05-01”;
(iii) SELECT H.Cname,R.RoomType FROM Hotel H,ROOM R WHERE H.ROOMID=R.ROOMID AND (Charges BETWEEN 2000 AND 3000);
(iv) (A) Select CNarre from Hotel where Hotel.RoomId=Room.RoomId and Floor=“First”;
Or
(B) Select Cname, DtofArrival, RoomType from Hotel, Room where Hotel.RoomID = Room.RoomId and month(DtofArrival)=“09”;

Question 35.
Consider the table Club whose fields are;

Write the Python code for the following:
Delete the record of those member whose name is Sachin.
Use the following for connection:
host = “local host”,
user = “Admin”,
passwd = “Admin@123”,
database = “System”
Answer:
import mysql.connector
mycon mysql.connector.connect (host =“local host”, user =“Admin”, passwd=“Admin@123”, database =“System”)
cursor mycon.cursor ( )
try:
cursor.execute (“DELETE FROM Club WHERE MemberName ‘Sachin’”)
cursor.commit ( )
except:
mycon.roll back ( )
mycon.close ( )

Section E
(2 × 5 = 10)

Question 36.
A file “Toys.csv” exists storing details of toys as per the following structure:
ToyID
Toyname
Category
Cost
Ananya is a Python developer at Toys Incorporation. Help her to write a program in Python with functions as follows:
(i) Which function helps to write multiple records to a csv file?
(ii) addToy() To append data of toys and store them to the file “Toys.csv” only if the Toy category is “Boys”. Also, display the number of toys added.
(iii) showToys() To open the file “Toys.csv” and display records of toys whose cost is above 1000.
Answer:
(i) writerows()
(ii) and (iii)
import csv
def addToy():
with open(“Toys.csv”, “a”) as f:
dt = writer(f)
tid=” ”
tname=” ”
cat=” ”
cost=0
while True:
tid= int(input(“Enter toyid:”))
tname = input(“Enter toy name:”)
cat = input(“Enter category:”)
cost= int(input(“Enter cost:”))
dt.writerow([tid.tname, cat, cost])
print(“Record has been added.”)
print(“Want to add more record? Type YES!!!”)
ch = input()
ch = ch.upper()
if ch==”YES”:
print(“___________”)
else:
break
f.close() //file closing is handled automatically by ‘with’
def showToys():
with open(“Toys.csv”, ‘r’) as tfile:
reader = csv.reader(tfile)
for row in reader:
if int(row[3])>1000:
print(row)
tfile. close()
addToy()
showToys()

Question 37.
Quick Learn University is setting up its academic blocks at Prayag Nagar and planning to set up a network. The university has three academic blocks and one human resource centre as shown in the diagram below:

Centre to centre distance between various blocks/centre is as follows:

Number of computers in each of the blocks/centre are as follows:

(i) Suggest the most suitable place (i.e. block/centre) to install the server of this university with a suitable reason.
(ii) Suggest an ideal layout for connecting these blocks/centres for wired connectivity.
(iii) Which device you will suggest to be placed/installed in each of these blocks/centre-to efficiently connect all the computers within these blocks/centre?
(iv) The university is planning to connect its admission office in the closest big city, which is more than 250 km from the university, which type of network out of LAN, MAN or WAN will be formed? Justify your answer.
(v) (a) Expand the following:
LAN
WAN
(b) Expand the following:
POP
TCP
Answer:
(i) The most suitable place to install the server is HR centre because it has maximum number of computers.
(ii)

(iii) Switch
(iv) WAN as it is another city.
(v) (A) LAN: Local Area Network
WAN: Wide Area Network
Or
(B) Post office protocol
Transmission control protocol