Important Questions and Answers for Class 11 Computer Science Chapter 8 Strings 2025-26

1. Multiple choice questions.

Q1. Which of the following is a valid way to declare a string in Python?

• (a) str1 = Hello World!
• (b) str1 = 'Hello World!'
• (c) str1 = "Hello World!"
• (d) Both (b) and (c)

Answer: (d) Both (b) and (c)

Q2. What is the output of the following code?
str1 = "Python"
print(str1[-1])

• (a) P
• (b) n
• (c) o
• (d) h

Answer: (b) n

Q3. Which string method would you use to check if a string starts with a particular substring?

• (a) startswith()
• (b) endswith()
• (c) isalpha()
• (d) strip()

Answer: (a) startswith()

Q4. What will be the result of "Hello" * 3 in Python?

• (a) Hello3
• (b) Hello Hello Hello
• (c) HelloHelloHello
• (d) Error

Answer: (c) HelloHelloHello

Q5. Which of the following statements about Python strings is TRUE?

• (a) They are mutable
• (b) String of length one is treated as character data type
• (c) They can be changed after creation
• (d) None of the above

Answer: (b) String of length one is treated as character data type

2. Very Short Answer (VSA).

Q1. What is a string in Python?

Answer: A string in Python is a sequence of one or more UNICODE characters enclosed within single, double, or triple quotes.

Q2. State the use of the len() function.

Answer: The len() function returns the total number of characters present in a string, including spaces and symbols.

Q3. What does it mean that strings are immutable in Python?

Answer: It means that once a string is created in Python, its contents cannot be changed or modified directly.

Q4. Name any two string operators in Python.

Answer: Concatenation operator (+) and repetition operator (*) are commonly used string operators in Python.

3. Short Answer Questions.

Q1. Explain how indexing works in Python strings with an example.

Answer: In Python, characters of a string are accessed using integer indexes. The first character has index 0. For example, in str1 = 'Hello', str1[0] gives 'H'. Negative indices access characters from the end, so str1[-1] is 'o'.

Q2. How is the slicing operation performed on strings? Give an example.

Answer: Slicing extracts a substring using the format string[start:end]. It starts at index 'start' and ends at 'end' (excluding end). For example, 'Python'[1:4] gives 'yth'. Slicing can also use a step value like string[::2].

Q3. State the difference between isupper() and islower() string methods in Python.

Answer: isupper() checks if at least one character is uppercase and the rest are non-alphabet or uppercase. islower() returns True if at least one character is lowercase and the remaining are lowercase or non-alphabetic.

Q4. Write a small code snippet to traverse a string using a while loop.

Answer: Example code:

str1 = "Python"
index = 0
while index < len(str1):
    print(str1[index], end='')
    index += 1

This prints all characters of str1 one by one.

4. Long Answer Questions.

Q1. Discuss various built-in string methods in Python, citing at least four with examples.

Answer: Python strings offer several built-in methods for manipulating text. For instance, upper() converts the string to uppercase, lower() converts it to lowercase, count() counts occurrences of a substring, and replace() replaces old substrings with new ones. For example, 'Python'.upper() returns 'PYTHON' while 'apple'.replace('a','A') gives 'Apple'. These methods help efficiently process string data.

1. Use upper() to capitalize all letters.
2. Use count() to find occurrences of a substring.
3. Use replace() to substitute substrings.
4. Use strip() to remove spaces from both ends.

Q2. Write and explain a user-defined function in Python that checks whether a string is a palindrome.

Answer: A palindrome is a string that reads the same backward as forward. To check for a palindrome, compare characters from the start and end of the string, moving towards the center. If all matched pairs are equal, the string is a palindrome. Otherwise, it’s not. Here is a program:

1. Set i = 0 and j = len(st) - 1.
2. While i <= j, compare st[i] with st[j].
3. If any pair differs, return False.
4. If all pairs match, return True.

Q3. Explain the concept of string immutability and how it affects string operations in Python.

Answer: String immutability means that once a string is created, its content cannot be changed directly. Operations like concatenation, replacement, or slicing always yield new strings instead of modifying the existing one. This ensures stability and avoids accidental modifications of string data in programs.

1. Assign a new value to a string variable if you want to "modify" it.
2. Using str1.replace() gives a new string, not changing str1.

4. True or False Questions.

Q1. Strings in Python can be modified after creation.

Answer: False

Q2. 'in' is a membership operator used to check for substrings in Python strings.

Answer: True

Q3. str1[1.5] is a valid statement to access characters in a Python string.

Answer: False

Q4. The strip() method removes spaces from both ends of a string.

Answer: True

5. Match the Following Questions.

Q1. Match the following string methods with their descriptions.

Questions	Answer
1. upper()	(A) Converts all characters to uppercase
2. join()	(B) Joins elements using a separator
3. find()	(C) Returns index of first occurrence of substring
4. strip()	(D) Removes whitespaces from both ends

Answer: 1 - A, 2 - B, 3 - C, 4 - D

Why learning string manipulation matters for Class 11 Computer Science?

• With Important questions class 11 computer science chapter 8 strings, students can understand how to manage, access, and change text data in Python.
• Practice here helps with string operations, preparing for practical coding and competitive exams.
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