Students must start practicing the questions from CBSE Sample Papers for Class 12 Computer Science with Solutions Set 10 are designed as per the revised syllabus.
CBSE Sample Papers for Class 12 Computer Science Set 10 with Solutions
Time: 3 Hours
Maximum Marks: 70
General Instructions
- This question paper contains 37 questions.
- All questions are compulsory. However, internal choices have been provided in some questions. Attempt only one of the choices in such questions.
- The paper is divided into 5 Sections – A, B, C, D and E.
- Section A consists of 21 questions (1 to 21). Each question carries 1 Mark.
- Section B consists of 7 questions (22 to 28). Each question carries 2 Marks.
- Section C consists of 3 questions (29 to 31). Each question carries 3 Marks.
- Section D consists of 4 questions (32 to 35). Each question carries 4 Marks.
- Section E consists of 2 questions (36 to 37). Each question carries 5 Marks.
- All programming questions are to be answered using Python Language only.
- 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 keys of a dictionary are mutable.
Answer:
False
Question 2.
Given an object obj1 = (10, 20, 30, 40, 50, 60, 70, 80, 90). What will be the output of print(obj1[3:7:2])?
(a) (40, 50, 60, 70, 80)
(b) (40, 50, 60, 70)
(c) (40, 50, 60)
(d) (40, 60)
Answer:
(d) (40, 60)
Question 3.
Which of the following expressions results in an error?
(a) float(’12’)
(b) int(’12’)
(c) float(‘12.5’)
(d) int(‘12.5’)
Answer:
(d) int(‘12.5’)
Question 4.
Given s1=”Olympics@France”. What will be the output of s1[2 : -3 : 2]
(a) ‘y@r’
(b) ‘pc@r’
(c) ‘ypc@r’
(d) None of these
Answer:
(c) ‘ypc@r’
Question 5.
What will be the output of the following code snippet?
Str = "KENDRIYA VIDYALAYA SANGATHAN JAMMU REGION" Str = Str.split() NewStr = Str[0] + "#" + Str[1] + "#" + Str[4] print (NewStr)
Answer:
KENDRIYA#VIDYALAYA#REGION
Question 6.
Evaluate the following expression and identify the correct answer.
16 – (4 + 2) * 5 + 2**3 * 4
(a) 54
(b) 46
(c) 18
(d) 32
Answer:
(c) 18
Question 7.
The output produced by the following code is:
try:
x=17
y=18
p=(x+y)%6 + y//5
except:
print("Error in execution")
else:
print("No errors")
finally:
print("Code executed")
Answer:
No errors
Code executed
Question 8.
Which among the following data structures can be edited?
(a) {}
(b) []
(c) ()
(d) Both (a) and (b)
Answer:
(d) Both (a) and (b)
Question 9.
Write the output of the following:
cal(m, n):
if m == n:
return m * 3
else:
return n * 2
cal("Amit", "Anuj")
print(s)
(a) AmitAmitAmit
(b) AmitAmit
(c) AnujAnujAnuj
(d) AnujAnuj
Answer:
(d) AnujAnuj
Question 10.
Write the missing statement to open the file such that the data record is appended to the file.
import pickle
f=open("abc.dat",_________)
pickle.dump([roll.name,marks],f)
f.close()
Answer:
“ab”
Question 11.
State True or False:
It is a must to handle exceptions in any code.
Answer:
False
Question 12.
Identify the output of the following Python statement.
lst1 = [10, 15, 20, 25, 30] lst1.insert(3, 4) lst1.insert(2, 3) print(lst1[-5])
(a) 2
(b) 3
(c) 4
(d) 20
Answer:
(b) 3
Question 13.
___________ is an attribute that links two tables to fetch corresponding
data.
(a) Primary key
(b) Secondary key
(c) Foreign key
(d) Composite key
Answer:
(c) Foreign key
Question 14.
What will the following query do?
Delete from Books where Bookname like "r_t%";
(a) Displays details of books whose names start with “r” and have 3rd letter as “t”.
(b) Removes records of books whose names start with “r” and have 3rd letter as “t”
(c) Removes records of books whose names start with “r”.
(d) None of the above
Answer:
(b) Removes records of books whose names start with “r” and have 3rd letter as “t”
Question 15.
Which of the following functions returns a part of a string?
(a) substr()
(b) mid()
(c) substring()
(d) Both (a) and (b)
Answer:
(b) Both (a) and (b)
Question 16.
The _________ clause can match a range of values in a field.
(a) range
(b) order
(c) between
(d) between values
Answer:
(c) between
Question 17.
Which of the following is the communication protocol that is used popularly for video conferencing?
(a) HTTP
(b) SGML
(c) VoIP
(d) HTTPS
Answer:
(c) VoIP
Question 18.
Which among the following is not a protocol?
(a) TCP
(b) PPP
(c) SGML
(d) HTTPS
Answer:
(c) SGML
Question 19.
What type of network topology has all devices connected to a central hub or switch?
Answer:
Star Topology
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 a correct explanation of A.
(b) Both A and R are true but R is not a correct explanation of A.
(c) A is true and R is false.
(d) A is false and R is true.
Question 20.
Assertion (A): Built-in functions are predefined in the system and can be directly used in any program.
Reason (R): id() and type() are built-in functions in Python.
Answer:
(b) Both A and R are true but R is not a correct explanation of A.
Question 21.
Assertion (A): The cardinality of a table can be increased by adding fields to the table.
Reason (R): Cardinality is number of records, adding fields will increase the degree.
Answer:
(d) A is false and R is true.
Section B
(7 × 2 = 14)
Question 22.
(i) Suppose there is a list such that: L=[2,3,4]. If we want to print this list in reverse order with an output of L=[4,3,2], which function/method should be used?
(ii) Which clause can sort a list in descending order.
Answer:
(i) List(reversed(L))
(ii) reverse=True
Question 23.
Give two examples each of membership and identity operators.
Answer:
Membership operators: in, not in
Identity operator: is, is not
Question 24.
Given Empdict={“Eno”: “E001″,”Ename”:”Jack”,”Dept”:”Accts”}
(I) (a) Write a statement to add the salary as 15000 into the dictionary.
Or
(b) Write a statement to modify the “Ename” to “Ananya”.
(II) (a) Write a statement to display the keys of the dictionary.
Or
(b) Write a statement to remove the key: value pair of “Dept”
Answer:
(I) (a) Empdict[“Salary”]=15000
Or
(b) Empdict[“Ename”]=”Ananya”
(II) (a) print(Empdict.keys()) Or (b) del Empdict["Dept"]
Question 25.
What are the possible outcome(s) executed from the following code? Also, specify the maximum and minimum values that can be assigned to the variable PICKER.
import random PICKER = random.randint(0, 3) COLOR = ["BLUE", "PINK", "GREEN", "RED"] for I in COLOR: for J in range (1, PICKER): print (I, end = " ") print ()
(a) BLUE – BLUE – PINK – BLUEBLUE
(b) PINK – BLUEPINK – PINKGREEN – PINKPINK
(c) GREEN – BLUEPINKGREEN – GREENRED – GREENGREEN
(d) RED – BLUEPINKGREENRED – REDRED
Answer:
Option (a) and (d) are possible
PICKER maxval = 3, minval = 0
Question 26.
Which constraint will restrict duplicate values in a field of a table? Which constraint allows to provision of business conditions in a field?
Answer:
To restrict duplicate values: A unique constraint can be applied.
To provide business conditions in a field: Check constraint.
Question 27.
(I) A table CUSTOMER has 10 columns but no row. Later, 10 new rows are inserted and 3 rows are deleted from the table. What is the degree and cardinality of the table CUSTOMER?
(a) What is the degree of the table CUSTOMER?
Or
(b) What is the cardinality of the table CUSTOMER?
(II) Observe the table CLUB given below:
(a) What is the cardinality and degree of the given table?
Or
(b) If a new column ContactNo is added and three more members join the club then how these changes will affect the degree and cardinality of the table.
Answer:
(I) (a) Degree = 10 (No. of columns)
Or
(b) Cardinality = 10 – 3 = 7 (no. of rows)
(II) (a) Cardinality: 4
Degree: 5
Or
(b) Cardinality: 7
Degree: 6
Question 28.
(a) Expand the following terms:
MAN, FTP
Or
(b) Name two switching techniques used to transfer data between two terminals(computers).
Answer:
(a) MAN – Metropolitan Area Network
FTP – File Transfer Protocol
Or
(b) Switching techniques used to transfer data between two terminals are
(i) Circuit switching
(ii) Packet switching
Section C
(3 × 3 = 9)
Question 29.
Write a function countEU() in Python, which should read each character of a text file IMP.TXT should count and display occurrence of alphabets E and U (including small cases e and u too).
e.g. If the file content is as follows:
Pinaky has gone to his friend’s house.
His friend’s name is Ravya. Her house is 12 km from Pinaky’s house.
The countEU() function should display the output as E : 8, U : 3
Or
Write a Python program to find the longest word in the file “status.txt”. If the contents of status.txt are
Welcome to your one-step solutions for all your study, practice, and assessment needs for various competitive and recruitment examinations and school segments. We have been working tirelessly for over a decade to make sure that you have best-in-class study resources because you deserve SUCCESS AND NOTHING LESS…
Output should be:
Longest word: examinations
Answer:
def countEU():
#Open the file in read mode
f = open("IMP.TXT", "r")
e = 0 # Initialize counter for 'E'/'e'
u = 0 # Initialize counter for 'U'/'u'
#Read fi1e line by line
while True:
l = f.readline()
if not l: #End of file break
#Count 'E'/'e' and 'U'/'u'
for i in l:
if i == 'E' or i == 'e':
e += 1
elif i == 'U' or i == 'u':
u+= 1
#Print the results
print("E:", e)
print("U:", u)
#Close the file
f.close()
# Call the function
countEU()
Or
def Longest():
f=open("status.txt")
words=f.read().split()
max_len=len(max(words, key=len))
for word in words:
if(len(word)==max_len):
print("Longest word:", word)
f.close()
Question 30.
(A) Julie has created a dictionary containing names and marks as key-value pairs of 6 students. Write a program, with separate user-defined functions to perform the following operations:
Push the keys (name of the student) of the dictionary into a stack, where the corresponding value (marks) is greater than 75.
Pop and display the content of the stack.
For example, If the sample content of the dictionary is as follows:
R={“OM”:76, “JAI”:45, “BOB”:89, “ALI”:65, “ANU”:90, “TOM”:82}
The output from the program should be
TOM ANU BOB OM
Or
(B) Write a Python program to input as many numbers and push them to a stack perfectstack[ ] using the function pushperfect(), only if the number input is perfect.
(A perfect number is one whose sum of factors other than itself, is equal to the number)
Answer:
(A) R={"OM":76, "JAI":45, "BOB":89, "ALI":65,"ANIT :90, "T0M":82}
def PUSH(S,N):
S.append(N)
def POP(S):
if S!=[]:
return S.pop()
else:
return None
ST=[ ]
for k in R:
if R[k]>=75:
PUSH(ST,k)
while True:
if ST!=[]:
print(POP(ST),end=" ")
else:
break
Or
(B) perfectstack =[]
def pushperfect(n) :
sum=0
for i in range(l,n):
if n%i==0:
sum+=i
if sum==n:
perfectstack.append(n)
ans='y'
while ans=='y':
n=input("Enter a number :")
pushperfect (n)
ans=input("Add more(y/n)")
Question 31.
Consider the table MOVIEDETAILS given below.
(A) Write statements to:
(i) Delete the records whose language is “English”.
(ii) Add a new record: “M050”, “Palki”,”Hindi”, 5,”Amazon Prime”.
(iii) Add a new column “DAYS” of type integer.
(B) (i) Remove the column “RATING”.
(ii) Display Title and language of movies played on “Hotstar”
(iii) Increase rating of “Hindi” movies by 2.
Answer:
(A) (i) DELETE FROM MOVIEDETAILS WHERE
LANGUAGE="ENGLISH":
(ii) INSERT INTO MOVIEDETAILS VALUES
("M050","Palki","Hindi", 5,"Amazon Prime"):
(iii) ALTER TABLE MOVIEDETAILS ADD DAYS INTEGER;
Or
(B) (i) ALTER TABLE MOVIEDETAILS DROP RATING;
(ii) Select Title. Language from MOVIEDETAILS
where Platform= "Hotstar";
(iii) Update MOVIEDETAILS set Rating = Rating +2
where Language= "hindi";
Section D
(4 × 4 = 16)
Question 32.
(A) (i) Differentiate else and except blocks in exception handling.
(ii) Write a code to open a file readme.txt and print all its contents. Report an error if the file doesn’t exist.
Or
(B) (i) When is a ValueError exception raised in Python?
(ii) Is it compulsory to write the final block in exception handling?
Answer:
(A) (i) except for Carrie’s code to handle/respond against the exception.
else Carries code that executes if no exception occurs.
(ii) try:
f1 = open ("readme.txt")
str = f1.read ()
print (str)
f1.close ()
except IOError:
print ("File doesn't Exist")
Or
(B) (i) Raised when a function gets an argument of correct type but improper value.
(ii) No, the final block is optional and carries code that will execute, irrespective of whether an exception occurs or not.
Question 33.
Mr. Roy is a programmer at KolkataSuppliers who maintains an inventory of miscellaneous products.
He is assigned to write a program using the following functions:
(I) getInventory() Write code to accept as many inventory records and store them in the csv file Inventory.csv storing records of inventory as per the following structure:
PCode Invname Price Reorder
(II) Display() To display the details stored in Inventory.csv
Answer:
import csv
def getInventory():
with open("Inventory.csv","a", newline="\n") as f: dt = csv.writer(f)
while True:
pcode= int(input("Enter Inventory code:"))
inv_name = input("Enter inventory name:")
price = eval(input("Enter Price:"))
rol = int(input("Enter reorder level :"))
dt.writerow([pcode, inv_name, price, rol])
print("Record has been added.")
print("Want to add more record?Type YES!!!")
ch = input()
ch = ch.upper()
if ch=="YES":
print ("*******************")
else:
break
def Display():
f = open("Inventory.csv","r")
dt = csv.reader(f)
data = list(dt)
f.close()
for i in data:
for j, in i:
print('\t', j, end=" ")
print()
getinventory()
Display()
Question 34.
Sarman maintains the following tables GARMENT and FABRIC, for his organization, storing details of garments and the fabric used in them. Write SQL commands for the statements (i) to (iv) to meet the following requirements:
(i) To display GCODE and DESCRIPTION of each GARMENT in descending order of GCODE.
(ii) To display the details of all the GARMENTS, which have READYDATE between 08-DEC-07 and 16-JUN-08 (inclusive of both dates).
(iii) To display the average PRICE of all the GARMENTS. Which are made up of FABRIC with FCODE as F03.
(iv) (A) To display details of all garments in descending order of Readydate.
Or
(B) To display Fcode wise number of garments.
Answer:
(i) SELECT GCODE, DESCRIPTION FROM GARMENT ORDER BY GCODE DESC: (ii) SELECT*FROM GARMENT WHERE READYDATE BETWEEN '08-DEC-07' AND '16-JUN-08': (iii) SELECT AVG(PRICE) FROM GARMENT WHERE FCODE = 'F03'; (iv) (A) Select *from Garments Order by ReadyDate desc; Or (B) Select Fcode, Count(*) from Garment Group by Fcode;
Question 35.
Consider the table Student whose fields are
Write the Python code to update the grade to ‘A’ for all these students who are getting more than 8 points.
The table structure is as follows:
Scode: integer
Name: varchar
Age: integer
Strcde: integer
Points: integer
Grade: varchar
Note the following to establish the connection between Python and MySQL:
Host: localhost
Username: Admin
Password: Admin@123
The table exists in MySQL database as: Student
Answer:
import mysql.connector as mydb con =mydb.connect(host "localhost", user "Admin",passwd "Admin@123", database "system") cursor=con.cursor ( ) sql="UPDATE Student SET Grade 'A' WHERE Points >8" try: cursor. execute (sql) con.commit ( ) except: con.roll back ( ) con.close ( )
Section E
(2 × 5 = 10)
Question 36.
Mr. Reena is a developer in file handling and has to write certain functions on csv files. She is confused with certain queries regarding the file type and the code writing. Help her in writing the code and in her queries.
(i) When do we use CSV file?
(ii) Write a program using two functions:
addCustomer() To write Customer code, Customer name, and Amt inthe file “cust.csv”
The details of the customers are as follows:
['CustCode', 'CustName', 'Amount'] ['001', 'Nihir', '8000'] ['104', 'Akshay', '5000']
readCustomer() To read the details of the customers and display them.
Answer:
(i) We can use CSV files when
- Data has a strict tabular structure.
- To transfer large data between programs.
- To import and export data.
(ii) import csv
def addCustomer ():
f1 = open('cust.csv', 'w', newline = "\n")
w1 = csv.writer(f1, delimiter = ";")
w1.writerow(['CustCode', 'CustName', 'Amount' ])
w1.writerow(['001', 'Nihir', '8000'])
w1.writerow(['104'. 'Akshay', '5000'])
f1.close()
def readCustomer():
with open("cust.csv", 'r',"\n") as file1:
reader = csv.reader(file1, delimiter = ";")
for row in reader:
print(row)
file1.close()
addCustomer()
readCustomer()
Question 37.
Red Pandas Infosystems has 4 blocks of buildings. The number of computers and distances among them is given below:
Answer the following questions concerning the above:
(i) Suggest a suitable cable layout for the network.
(ii) Suggest the best place to house the server of the network.
(iii) Which topology should be used to connect computers in each building?
(iv) What kind of network will be formed here? (LAN/MAN/WAN)
(v) Write one advantage of the topology suggested by you.
Or
Write one disadvantage of the topology suggested by you.
Answer:
(i) The cable layout is given below:
(ii) ADMIN building, as it has the maximum number of computers.
(iii) Star topology, as it is the topology offering the best facilities.
(iv) LAN – Local Area Network
(v) (A) Fault detection is easy.
Or
(B) Central node dependency