Important Questions and Answers for Class 11 Computer Science Chapter 9 Lists 2025-26

Q1. Which of the following is the correct way to declare a list in Python?

• (a) list1 = (1,2,3,4)
• (b) list1 = [1,2,3,4]
• (c) list1 = {1,2,3,4}
• (d) list1 = "1,2,3,4"

Answer: (b) list1 = [1,2,3,4]

Q2. Which method is used to add multiple elements from another iterable to the end of a list?

• (a) append()
• (b) extend()
• (c) insert()
• (d) count()

Answer: (b) extend()

Q3. What will be the output of the expression len([10, 20, 30])?

• (a) 2
• (b) 30
• (c) 3
• (d) 0

Answer: (c) 3

Q4. Which operator is used to concatenate two lists in Python?

• (a) *
• (b) -
• (c) +
• (d) /

Answer: (c) +

Q5. What is the data type of the following? ['a', [1,2,3], 4.5]

• (a) Dictionary
• (b) Tuple
• (c) List
• (d) String

Answer: (c) List

2. Very Short Answer (VSA).

Q1. What is a list in Python?

Answer: A list is an ordered, mutable sequence of elements in Python, which can contain items of different data types like integers, strings, or other lists.

Q2. How can you access the last element of a list named myList?

Answer: The last element of myList can be accessed using myList[-1].

Q3. Name any two built-in functions that can be used with lists in Python.

Answer: Two built-in functions for lists are len() and sum().

Q4. Which operator allows you to repeat the elements of a list?

Answer: The * operator is used to repeat the elements of a list in Python.

Q5. What is a nested list?

Answer: A nested list is a list that contains one or more lists as its elements.

3. Short Answer Questions.

Q1. Explain the difference between append() and extend() methods in lists.

Answer: The append() method adds its argument as a single element to the end of a list, even if the argument is another list. In contrast, extend() adds each element of the given iterable (such as a list) as separate elements to the target list.

Q2. How are lists mutable? Give an example.

Answer: Lists are mutable, meaning their elements can be changed after creation. For example, colors = ['red', 'blue', 'green']; doing colors[1] = 'yellow' changes the second element to 'yellow'.

Q3. What will be the output of list1 = [1, 2, 3, 4].append([5, 6]) and why?

Answer: The result will be [1, 2, 3, 4, [5, 6]] because append() adds the entire list [5, 6] as a single element at the end of list1.

Q4. Explain how you can traverse a list using a for loop.

Answer: To traverse a list with a for loop, write for element in listName: and process each element in the loop body. This way, every item in the list is accessed one by one.

4. Long Answer Questions.

Q1. Describe three different methods to copy a list in Python and explain the difference between assignment and copying.

Answer: Assigning a list to another variable (e.g., list2 = list1) only creates an alias; both variables point to the same object. To make an actual copy, you can use slicing (list2 = list1[:]), the list() constructor (list2 = list(list1)), or the copy.copy() function. These methods create a new, independent list object that does not reflect changes made to the original. This is important to avoid accidental modification of data.

1. Assignment creates an alias—not a copy.
2. Slicing: list1[:] gives a shallow copy.
3. list(list1) or copy.copy(list1) also create new, shallow copies.

Q2. Explain different list operations (concatenation, repetition, membership, slicing) with examples.

Answer: Concatenation combines two lists using +, e.g., [1,2]+[3,4] gives [1,2,3,4]. Repetition uses *, so [1,2]*3 is [1,2,1,2,1,2]. Membership checks elements: 2 in [1,2,3] is True. Slicing extracts parts of a list: [1,2,3,4][1:3] gives [2,3].

1. Concatenation: [a]+[b] merges two lists.
2. Repetition: list1*2 repeats elements.
3. Membership: x in list1 checks presence.
4. Slicing: list1[start:end:step] extracts sublists.

Q3. Write a Python function to increment all the elements in a given list by 5. Show how passing this list to a function modifies the original list. Explain the output using the concept of mutability.

Answer: Define a function def increment(lst): for i in range(len(lst)): lst[i] += 5. When the list is passed to this function, its elements are changed because lists are mutable. Thus, the original list is updated after the function call without creating a new list.

1. Define the function with the list parameter.
2. Modify each element by adding 5 inside the loop.
3. Pass the original list to this function.
4. After the function call, the original list reflects the changes.

4. True or False Questions.

Q1. Lists in Python can only store elements of a single data type.

Answer: False.

Q2. The expression list1[-1] returns the first element of the list.

Answer: False.

Q3. Using list1.extend([4,5]) adds 4 and 5 as separate elements to list1.

Answer: True.

Q4. Lists are mutable, so elements can be changed after creation.

Answer: True.

Q5. The pop() method removes the first element from a list by default.

Answer: False.

5. Match the Following Questions.

Q1. Match the following list methods with their correct descriptions.

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

Why Learning Lists Matters in Class 11 Computer Science?

Understanding Python lists is essential for Class 11 Computer Science. These important questions help you practise exam-oriented concepts, such as data types, list operations, and traversing.

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