Question 1

Which of the following identifier names are invalid and why?

a) Serial_no.
b) 1st_Room
c) Hundred$
d) Total Marks
e) Total_Marks
f) total-Marks
g) Percentage
h) True

Accepted Answer

Invalid identifiers are:
- Serial_no.: Invalid because it contains a dot (.) which is not allowed in identifiers.
- 1st_Room: Invalid because identifiers cannot start with a digit.
- Hundred$: Invalid because $ is not allowed in identifiers.
- Total Marks: Invalid because spaces are not allowed in identifiers.
- total-Marks: Invalid because hyphen (-) is not allowed in identifiers.
- True: Invalid because it is a reserved keyword in Python.
Valid identifiers are:
- Total_Marks
- Percentage — In Python, identifiers must start with a letter (A-Z or a-z) or underscore (_), followed by letters, digits (0-9), or underscores. They cannot contain spaces, dots, hyphens, or special characters like $. Also, keywords like True cannot be used as identifiers.

Question 2

Write the corresponding Python assignment statements:
a) Assign 10 to variable length and 20 to variable breadth.
b) Assign the average of values of variables length and breadth to a variable sum.
c) Assign a list containing strings 'Paper', 'Gel Pen', and 'Eraser' to a variable stationery.
d) Assign the strings 'Mohandas', 'Karamchand', and 'Gandhi' to variables first, middle and last.
e) Assign the concatenated value of string variables first, middle and last to variable fullname. Make sure to incorporate blank spaces appropriately between different parts of names.

Accepted Answer

a) length = 10
   breadth = 20

b) sum = (length + breadth) / 2

c) stationery = ['Paper', 'Gel Pen', 'Eraser']

d) first = 'Mohandas'
   middle = 'Karamchand'
   last = 'Gandhi'

e) fullname = first + ' ' + middle + ' ' + last — Assignment statements in Python use the '=' operator. For average, sum of length and breadth is divided by 2. Lists are defined using square brackets []. String concatenation uses '+' operator and spaces are added as ' '.

Question 3

Which data type will be used to represent the following data values and why?
a) Number of months in a year
b) Resident of Delhi or not
c) Mobile number
d) Pocket money
e) Volume of a sphere
f) Perimeter of a square
g) Name of the student
h) Address of the student

Accepted Answer

a) Integer (int) - because number of months is a whole number.
b) Boolean (bool) - because it is a yes/no (True/False) condition.
c) String (str) - because mobile numbers may start with zero and are not used for calculations.
d) Float (float) - because pocket money can have decimal values.
e) Float (float) - volume can be a decimal value.
f) Float (float) - perimeter can be decimal if side length is decimal.
g) String (str) - names are textual data.
h) String (str) - address is textual data. — Data types are chosen based on the nature of data. Whole numbers use int, true/false conditions use bool, textual data use str, and decimal numbers use float.

Question 4

Give the output of the following when num1 = 4, num2 = 3, num3 = 2
a) num1 += num2 + num3
b) print (num1)
c) num1 = num1 ** (num2 + num3)
d) print (num1)
e) num1 **= num2 + c
f) num1 = '5' + '5'
g) print(num1)
h) print(4.00/(2.0+2.0))
i) num1 = 2+9*((3*12)-8)/10
j) print(num1)
k) num1 = float(10)
l) print (num1)
m) num1 = int('3.14')
n) print (num1)
o) print(10 != 9 and 20 >= 20)
p) print(5 % 10 + 10 < 50 and 29 <= 29)

Accepted Answer

Given num1=4, num2=3, num3=2: a) num1 += num2 + num3 => num1 = 4 + 3 + 2 = 9 b) print(num1) => 9 c) num1 = num1 ** (num2 + num3) => num1 = 9 ** (3 + 2) = 9 ** 5 = 59049 d) print(num1) => 59049 e) num1 **= num2 + c => Error: 'c' is undefined, causes runtime error f) num1 = '5' + '5' => '55' g) print(num1) => 55 h) print(4.00/(2.0+2.0)) => 4.00/4.0 = 1.0 i) num1 = 2+9*((3*12)-8)/10 => 2 + 9*(36-8)/10 = 2 + 9*28/10 = 2 + 252/10 = 2 + 25.2 = 27.2 j) print(num1) => 27.2 k) num1 = float(10) => 10.0 l) print(num1) => 10.0 m) num1 = int('3.14') => Error: invalid literal for int() with base 10 n) print(num1) => Not reached due to error in m o) print(10 != 9 and 20 >= 20) => True and True = True p) print(5 % 10 + 10 < 50 and 29 <= 29) => (5 + 10) < 50 and True => 15 < 50 and True => True and True = True — Step-by-step evaluation: - += adds sum of num2 and num3 to num1. - ** is exponentiation. - String concatenation with '+' joins strings. - Division with floats returns float. - int('3.14') causes ValueError because '3.14' is not an integer string. - Logical operators and comparison operators return boolean values.

Question 5

Categorise the following as syntax error, logical error or runtime error:
a) 25 / 0
b) num1 = 25; num2 = 0; num1 / num2

Accepted Answer

a) 25 / 0 => Runtime error (ZeroDivisionError) because division by zero is undefined.
b) num1 = 25; num2 = 0; num1 / num2 => Runtime error (ZeroDivisionError) for same reason. — Syntax errors occur due to incorrect code structure, logical errors occur when code runs but produces wrong results, runtime errors occur during execution like division by zero.

Question 6

Write a Python program to calculate the amount payable if money has been lent on simple interest. Principal or money lent = P, Rate = R% per annum and Time = T years. Then Simple Interest (SI) = (P x R x T) / 100.

Amount payable = Principal + SI.

P, R and T are given as input to the program.

Accepted Answer

Python program:

P = float(input('Enter principal amount: '))
R = float(input('Enter rate of interest: '))
T = float(input('Enter time in years: '))

SI = (P * R * T) / 100
Amount_payable = P + SI

print('Simple Interest:', SI)
print('Amount payable:', Amount_payable) — Inputs are taken as float to allow decimal values. Simple Interest formula is applied and amount payable is sum of principal and interest. Outputs are printed.

Question 7

Write a program to repeat the string "GOOD MORNING" n times. Here n is an integer entered by the user.

Accepted Answer

Python program:

n = int(input('Enter number of times to repeat: '))
print('GOOD MORNING ' * n) — The string is multiplied by integer n to repeat it n times. Input is converted to int.

Question 8

Write a program to find the average of 3 numbers.

Accepted Answer

Python program:

num1 = float(input('Enter first number: '))
num2 = float(input('Enter second number: '))
num3 = float(input('Enter third number: '))
average = (num1 + num2 + num3) / 3
print('Average:', average) — Inputs are taken as float to allow decimal numbers. Average is sum divided by 3.

Question 9

Write a program that asks the user to enter one's name and age. Print out a message addressed to the user that tells the user the year in which he/she will turn 100 years old.

Accepted Answer

Python program:

name = input('Enter your name: ')
age = int(input('Enter your age: '))
current_year = 2026  # or use import datetime to get current year dynamically
year_turn_100 = current_year + (100 - age)
print(f'{name}, you will turn 100 years old in the year {year_turn_100}.') — Age is subtracted from 100 to find years left, added to current year to find target year. Input name and age are taken from user.

Question 10

What is the difference between else and elif construct of if statement?

Accepted Answer

The 'elif' (else if) construct allows checking multiple conditions sequentially after the initial 'if'. It is used when there are multiple conditions to test.
The 'else' construct is used as a default block that executes when none of the preceding 'if' or 'elif' conditions are true. — 'elif' provides additional conditional checks, whereas 'else' is the fallback when all conditions fail.

Question 11

Find the output of the following program segments:
a) for i in range(20,30,2):
   print(i)
b) country = 'INDIA'
   for i in country:
       print (i)
c) i = 0; sum = 0
   while i < 9:
       if i % 4 == 0:
           sum = sum + i
       i = i + 2
   print (sum)

Accepted Answer

a) Output:
20
22
24
26
28

b) Output:
I
N
D
I
A

c) Execution:
i=0,sum=0
Loop while i<9:
 i=0: 0%4=0 True sum=0+0=0 i=0+2=2
 i=2: 2%4=2 False sum=0 i=2+2=4
 i=4: 4%4=0 True sum=0+4=4 i=4+2=6
 i=6: 6%4=2 False sum=4 i=6+2=8
 i=8: 8%4=0 True sum=4+8=12 i=8+2=10
Loop ends (i=10 >=9)
print(sum) => 12 — a) range(20,30,2) generates numbers from 20 to 28 stepping by 2.
b) Looping over string prints each character.
c) The while loop adds i to sum only if i divisible by 4, increments i by 2 each time.

Question 12

Identify the personal details of students from your school identity card and write a program to accept these details for all students of your school and display them in this format.

Format:
Name of School
Student Name: PQR
Roll No: 99
Class: XI
Section: A
Address: Address Line 1
Address Line 2
City: ABC
Pin Code: 999999
Parent's/ Guardian's Contact No: 9999999999

Accepted Answer

Sample Python program:

num_students = int(input('Enter number of students: '))

for _ in range(num_students):
    print('Name of School')
    name = input('Student Name: ')
    roll_no = input('Roll No: ')
    class_name = input('Class: ')
    section = input('Section: ')
    address1 = input('Address Line 1: ')
    address2 = input('Address Line 2: ')
    city = input('City: ')
    pin_code = input('Pin Code: ')
    parent_contact = input("Parent's/ Guardian's Contact No: ")

print(f'Student Name: {name}')
    print(f'Roll No: {roll_no}')
    print(f'Class: {class_name}')
    print(f'Section: {section}')
    print(f'Address: {address1}')
    print(address2)
    print(f'City: {city}')
    print(f'Pin Code: {pin_code}')
    print(f"Parent's/ Guardian's Contact No: {parent_contact}")
    print() — The program loops over the number of students, takes input for each detail, and prints in the required format. This automates data entry and display.

Question 13

What is a program in the context of computer programming?

Accepted Answer

A set of instructions or commands executed by a computer — A program is defined as an ordered set of instructions or commands that a computer executes to perform a specific task.

Question 14

Who created the Python programming language and in which year?

Accepted Answer

Guido van Rossum in 1991 — Python was created by Guido van Rossum in 1991 and is known for its simplicity and versatility.

Question 15

Which of the following is NOT a Python keyword?

Accepted Answer

function — The word 'function' is not a reserved keyword in Python; keywords like while, lambda, and pass are reserved.

Brief Overview Chapter of Python

Brief Overview Chapter of Python — Study Notes

3.1 INTRODUCTION TO PYTHON

3.1.2 Execution Modes

3.2 Python Keywords

Practice Questions — Brief Overview Chapter of Python

All 8 Chapters in Informatics Practices