Computer Science (Python) Sample 2022-2023 Commerce (English Medium) Class 12 Question Paper Solution

State True or False.

“Variable declaration is implicit in Python.”

True

False

Which of the following is an invalid datatype in Python?

Set

None

Integer

Real

Given the following dictionaries.

dict_exam={"Exam":"AISSCE", "Year":2023}
dict_result={"Total":500, "Pass_Marks":165}

Which statement will merge the contents of both dictionaries?

dict_exam.update(dict_result)

dict_exam + dict_result

dict_exam.add(dict_result)

dict_exam.merge(dict_result)

Consider the given expression:

not True and False or True

Which of the following will be the correct output if the given expression is evaluated?

True

False

NONE

NULL

Select the correct output of the code:

a = "Year 2022 at All the best"
a = a.split('2')
b = a[0] + ". " + a[1] + ". " + a[3]
print (b)

Year . 0. at All the best

Year 0. at All the best

Year . 022. at All the best

Year . 0. at all the best

Which of the following mode in the file opening statement results or generates an error if the file does not exist?

a+

r+

w+

None of the above

______ command is used to remove the primary key from a table in SQL.

update

remove

alter

drop

Which of the following commands will delete the table from the MYSQL database?

DELETE TABLE

DROP TABLE

REMOVE TABLE

ALTER TABLE

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

S="Welcome to class XII" # Statement 1
print(S)       #Statement 2
S="Thank you"    # Statement 3
S[0]= '@'      # Statement 4
S=S+"Thank you"   # Statement 5

Statement 3

Statement 4

Statement 5

Statements 4 and 5

______ is a non-key attribute, whose values are derived from the primary key of some other table.

Primary Key

Foreign Key

Candidate Key

Alternate Key

The correct syntax of seek() is ______

file_object.seek(offset [, reference_point])

seek(offset [, reference_point])

seek(offset, file_object)

seek.file_object(offset)

The SELECT statement when combined with the ______ clause returns records without repetition.

DESCRIBE

UNIQUE

DISTINCT

NULL

______ is a communication methodology designed to deliver both voice and multimedia communications over Internet protocol.

VoIP

SMTP

PPP

HTTP

What will the following expression be evaluated for in Python?

print(15.0 / 4 + (8 + 3.0))

14.75

14.0

15

15.5

Which function is used to display the total number of records from a table in a database?

sum(*)

total(*)

count(*)

return(*)

To establish a connection between Python and SQL databases, connect() is used. Which of the following arguments may not necessarily be given while calling connect()?

host

database

user

password

Assertion (A): If the arguments in function call statement match the number and order of arguments as defined in the function definition, such arguments are called positional arguments.

Reasoning (R): During a function call, the argument list first contains default argument(s) followed by the positional argument(s).

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

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

A is True but R is False.

A is false but R is True.

Assertion (A): CSV (Comma Separated Values) is a file format for data storage that looks like a text file.

Reason (R): The information is organized with one record on each line and each field is separated by a comma.

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

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

A is True but R is False.

A is false but R is True.

Rao has written a code to input a number and check whether it is prime or not. His code is having errors. Rewrite the correct code and underline the corrections made.

def prime():
n=int(input("Enter number to check :: ")
for i in range (2, n//2):
if n%i=0:
print("Number is not prime \n")
break
else:
print("Number is prime \n’)

Write two points of difference between Circuit Switching and Packet Switching.

Write two points of difference between XML and HTML.

Given is a Python string declaration:

myexam="@@CBSE Examination 2022@@"

Write the output of: 

print(myexam[::-2])

Write the output of the code given below:

my_dict = {"name": "Aman", "age": 26}
my_dict['age'] = 27
my_dict['address'] = "Delhi"
print(my_dict.items())

Explain the use of ‘Foreign Key’ in a Relational Database Management System. Give example to support your answer.

Write the full form of the following:

SMTP

Write the full form of the following:

PPP

What is the use of TELNET?

Predict the output of the Python code given below:

def Diff(N1,N2):
 if N1>N2:
 return N1-N2
 else:
 return N2-N1

NUM= [10,23,14,54,32]
for CNT in range (4,0,-1):
 A=NUM[CNT]
 B=NUM[CNT-1]
 print(Diff(A,B),'#', end=' ')

Predict the output of the Python code given below:

tuple1 = (11, 22, 33, 44, 55 ,66)
list1 =list(tuple1)
new_list = []
for i in list1:
 if i%2==0:
 new_list.append(i)
new_tuple = tuple(new_list)
print(new_tuple)

Differentiate between count() and count(*) functions in SQL with appropriate examples.

Categorize the following commands as DDL or DML:

INSERT, UPDATE, ALTER, DROP

Consider the following tables – Bank_Account and Branch:

Table: Bank_Account

Table: Branch

What will be the output of the following statement?

SELECT * FROM Bank_Account NATURAL JOIN Branch;

Write the output of the queries based on the table, TECH_COURSE given below:

1. SELECT DISTINCT TID FROM TECH_COURSE;
2. SELECT TID, COUNT(*), MIN(FEES) FROM TECH_COURSE GROUP BY TID HAVING COUNT(TID)>1;
3. SELECT CNAME FROM TECH_COURSE WHERE FEES>15000 ORDER BY CNAME;
4. SELECT AVG(FEES) FROM TECH_COURSE WHERE FEES BETWEEN 15000 AND 17000;

Write a method COUNTLINES() in Python to read lines from the text file ‘TESTFILE.TXT’ and display the lines which do not start with any vowel.

Example:

If the file content is as follows:

An apple a day keeps the doctor away.
We all pray for everyone’s safety.
A marked difference will come in our country.

The COUNTLINES() function should display the output as:

The number of lines not starting with any vowel - 1

Write a function ETCount() in Python, which should read each character of a text file “TESTFILE.TXT” and then count and display the count of occurrence of alphabets E and T individually (including small cases e and t too).

Example:

If the file content is as follows:

Today is a pleasant day.
It might rain today.
It is mentioned on weather sites

The ETCount() function should display the output as:
E or e : 6
T or t : 9

Write the outputs of the SQL queries based on the relations Teacher and Placement given below:

Table: Teacher

Table: Placement

1. SELECT Department, avg(salary) FROM Teacher GROUP BY Department;
2. SELECT MAX(Date_of_Join), MIN(Date_of_Join) FROM Teacher;
3. SELECT Name, Salary, T.Department, Place FROM Teacher T, Placement P WHERE T.Department = P.Department AND Salary>20000;
4. SELECT Name, Place FROM Teacher T, Placement P WHERE Gender = ’F’ AND T.Department = P.Department;

Write the command to view all tables in a database.

Write a function INDEX_LIST(L), where L is the list of elements passed as arguments to the function. The function returns another list named ‘indexList’ that stores the indices of all Non-Zero Elements of L.

For example:

If L contains [12, 4, 0, 11, 0, 56]

The indexList will have - [0, 1, 3, 5].

A list contains the following record of a customer: [Customer_name, Phone_number, City]

Write the following user-defined functions to perform given operations on the stack named ‘status’:

1. Push_element() - Push an object containing the name and Phone number of customers who live in Goa to the stack.
2. Pop_element() - Pop the objects from the stack and display them. Also, display “Stack Empty” when there are no elements in the stack.

For example:

If the lists of customer details are:

[“Gurdas”, “99999999999”,”Goa”]
[“Julee”, “8888888888”,”Mumbai”] [“Murugan”,”77777777777”,”Cochin”]
[“Ashmit”, “1010101010”,”Goa”]

The stack should contain

[“Ashmit”,”1010101010”]
[“Gurdas”,”9999999999”]

The output should be:

[“Ashmit”,”1010101010”]
[“Gurdas”,”9999999999”]
Stack Empty

Write a function in Python, Push(SItem) where SItem is a dictionary containing the details of stationery items - {Sname:price}. The function should push the names of those items in the stack that have a price greater than 75. Also, display the count of elements pushed into the stack.

For example:

If the dictionary contains the following data:

Ditem={"Pen":106,"Pencil":59,"Notebook":80,"Eraser":25}

The stack should contain
Notebook
Pen

The output should be:
The count of elements in the stack is 2

MakeInIndia Corporation, a Uttarakhand-based IT training company, is planning to set up training centres in various cities in the next 2 years. Their first campus is coming up in the Kashipur district. At the Kashipur campus, they are planning to have 3 different blocks for App development, Web designing, and Movie editing. Each block has a number of computers, which are required to be connected to a network for communication, data, and resource sharing. As a network consultant of this company, you have to suggest the best network-related solutions for the issues/problems raised in questions keeping in mind the distances between various blocks/locations and other given parameters.

Distance between various blocks/locations:

Number of computers

1. Suggest the most appropriate block/location to house the SERVER in the Kashipur campus (out of the 3 blocks) to get the best and most effective connectivity. Justify your answer.
2. Suggest a device/software be installed in the Kashipur Campus to take care of data security.
3. Suggest the best-wired medium and draw the cable layout (Block to Block) to economically connect various blocks within the Kashipur Campus.
4. Suggest the placement of the following devices with appropriate reasons:
   a. Switch/Hub
   b. Repeater
5. Suggest a protocol that shall be needed to provide a Video Conferencing solution between Kashipur Campus and Mussoorie Campus.

Write the output of the code given below:

p=5
def sum(q,r=2):
      global p
      p=r+q**2
      print(p, end= '#')

a=10
b=5
sum(a,b)
sum(r=5,q=1)

The code given below inserts the following record in the table Student:

RollNo - integer
Name - string
Clas - integer
Marks - integer

Note the following to establish connectivity between Python and MYSQL:

• Username is root
• Password is tiger
• The table exists in an MYSQL database named school.
• The details (RollNo, Name, Clas and Marks) are to be accepted by the user.

Write the following missing statements to complete the code:

Statement 1 - to form the cursor object.

Statement 2 - to execute the command that inserts the record in the table Student.

Statement 3 - to add the record permanently to the database.

import mysql.connector as mysql
def sql_data():
        con1=mysql.connect(host="localhost",user="root",password="tiger", database="school")
 mycursor=_________________ #Statement 1 
 rno=int(input("Enter Roll Number :: "))
 name=input("Enter name :: ")
 clas=int(input("Enter class :: "))
 marks=int(input("Enter Marks :: "))
 querry="insert into student 
values({},'{}',{},{})".format(rno,name,clas,marks)
--------------------#Statement 2
--------------------# Statement 3
 print("Data Added successfully")

Predict the output of the code given below:

s="welcome2cs" 

n = len(s)
m=""
for i in range(0, n):
       if (s[i] >= 'a' and s[i] <= 'm'):
            m = m +s[i].upper()
 elif (s[i] >= 'n' and s[i] <= 'z'):
          m = m +s[i-1]
 elif (s[i].isupper()):
     m = m + s[i].lower()
 else:
     m = m +'&'
print(m)

The code given below reads the following record from the table named student and displays only those records that have marks greater than 75:

• RollNo - integer
• Name - string
• Clas - integer
• Marks - integer

Note the following to establish connectivity between Python and MYSQL:

• Username is root.
• The password is the tiger.
• The table exists in an MYSQL database named school.

Write the following missing statements to complete the code:

Statement 1 - to form the cursor object
Statement 2 - to execute the query that extracts records of those students whose marks are greater than 75.
Statement 3 - to read the complete result of the query (records whose marks are greater than 75) into the object named data, from the table student in the database.

import mysql.connector as mysql
def sql_data():
       con1=mysql.connect(host="localhost",user="root",password="tiger", database="school")
       mycursor=_______________ #Statement 1
       print("Students with marks greater than 75 are :")
                  _________________________ #Statement 2
                 data=__________________ #Statement 3
                for i in data:
                   print(i)
                print()

What is the advantage of using a CSV file for permanent storage? Write a Program in Python that defines and calls the following user-defined functions:

1. ADD() - To accept and add data of an employee to a CSV file ‘record.csv’. Each record consists of a list with field elements such as empid, name, and mobile to store an employee id, employee name, and employee salary respectively.
2. COUNTR() - To count the number of records present in the CSV file named ‘record.csv’.

Give any one point of difference between a binary file and a CSV file. Write a Program in Python that defines and calls the following user-defined functions:

1. add() - To accept and add data of an employee to a CSV file ‘furdata.csv’. Each record consists of a list with field elements such as fid, fname, and fprice to store furniture id, furniture name, and furniture price respectively.
2. search() - To display the records of the furniture whose price is more than 10000.

Navdeep creates a table RESULT with a set of records to maintain the marks secured by students in Sem1, Sem2, Sem3, and their divisions. After the creation of the table, he entered data of 7 students in the table.

Based on the data given above answer the following questions:

1. Identify the most appropriate column, which can be considered as the Primary key.
2. If two columns are added and 2 rows are deleted from the table result, what will be the new degree and cardinality of the above table?
3. Write the statements to:
   a. Insert the following record into the table
   Roll No - 108, Name - Aadit, Sem1- 470, Sem2 - 444, Sem3 - 475, Div - I.
   b. Increase the SEM2 marks of the students 3% whose name begins with ‘N’.
   OR
   Write the statements to:
   a. Delete the record of students securing IV division.
   b. Add a column REMARKS in the table with datatype as varchar with 50 characters.

Aman is a Python programmer. He has written a code and created a binary file record.dat with employeeid, ename, and salary. The file contains 10 records.

He now has to update a record based on the employee id entered by the user and update the salary. The updated record is then to be written in the file temp.dat. The records which are not to be updated also have to be written to the file temp.dat. If the employee id is not found, an appropriate message should be displayed.

As a Python expert, help him to complete the following code based on the requirement given above:

import _______ #Statement 1
def update_data():
rec={}
fin=open("record.dat","rb") 
fout=open("_____________") #Statement 2
found=False
eid=int(input("Enter employee id to update their salary :: "))
while True:
try:
rec=______________ #Statement 3
if rec["Employee id"]==eid:
 found=True 
   rec["Salary"]=int(input("Enter new salary :: "))
   pickle.____________ #Statement 4
else:
   pickle.dump(rec,fout)
except:
  break
if found==True:
print("The salary of employee id ",eid," has
been updated.")
else:
print("No employee with such id is not found")
 fin.close()
fout.close()

1. Which module should be imported into the program? (Statement 1)
2. Write the correct statement required to open a temporary file named temp.dat. (Statement 2)
3. Which statement should Aman fill in Statement 3 to read the data from the binary file, record.dat, and in Statement 4 to write the updated data in the file, temp.dat?