Computer Science Chapter 1 Computer System – NCERT Solutions for Class 11

Exercise

1. What will be the output of the following statements?
   
   i.

   list1 = [12,32,65,26,80,10]
   list1.sort()
   print(list1)
       

   
   

   Answer: [10, 12, 26, 32, 65, 80]

   
   ii.

   list1 = [12,32,65,26,80,10]
   sorted(list1)
   print(list1)
       

   
   

   Answer: [12, 32, 65, 26, 80, 10]

   
   iii.

   list1 = [1,2,3,4,5,6,7,8,9,10]
   list1[::-2]
   list1[:3] + list1[3:]
       

   
   

   Answer: list1[::-2] results in [10, 8, 6, 4, 2], and list1[:3] + list1[3:] results in [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]

   
   iv.

   list1 = [1,2,3,4,5]
   list1[len(list1)-1]
       

   Answer: 5

   
   
2. Consider the following list myList. What will be the elements of myList after the following two operations:

   myList = [10,20,30,40]
   i. myList.append([50,60])
   ii. myList.extend([80,90])
       

   Answer: After the first operation, myList becomes [10, 20, 30, 40, [50, 60]]. After the second operation, myList becomes [10, 20, 30, 40, [50, 60], 80, 90].

   
   
3. What will be the output of the following code segment:

   myList = [1,2,3,4,5,6,7,8,9,10]
   for i in range(0,len(myList)):
       if i%2 == 0:
           print(myList[i])
       

   Answer: The output will be:
   1
   3
   5
   7
   9

   
   
4. What will be the output of the following code segment:

   a. myList = [1,2,3,4,5,6,7,8,9,10]
   del myList[3:]
   print(myList)
   b. myList = [1,2,3,4,5,6,7,8,9,10]
   del myList[:5]
   print(myList)
   c. myList = [1,2,3,4,5,6,7,8,9,10]
   del myList[::2]
   print(myList)
       

   Answer:
   a. [1, 2, 3]
   b. [6, 7, 8, 9, 10]
   c. [2, 4, 6, 8, 10]

   
   
5. Differentiate between append() and extend() functions of list.

   Answer: append() adds its argument as a single element to the end of the list (can be a value or even another list as a single item), while extend() adds elements from the iterable (like another list) one by one to the end of the list.

   
   
6. Consider a list:

   list1 = [6,7,8,9]
       

   What is the difference between the following operations on list1:
   a. list1 * 2
   b. list1 *= 2
   c. list1 = list1 * 2

   Answer:

   • a. list1 * 2 produces [6, 7, 8, 9, 6, 7, 8, 9], but does not change list1.
   • b. list1 *= 2 modifies list1 in-place and makes it [6, 7, 8, 9, 6, 7, 8, 9].
   • c. list1 = list1 * 2 creates a new list [6, 7, 8, 9, 6, 7, 8, 9] and assigns it to list1.
   
   
7. The record of a student (Name, Roll No., Marks in five subjects and percentage of marks) is stored in the following list:

   stRecord = ['Raman','A-36',[56,98,99,72,69],78.8]
       

   Write Python statements to retrieve the following information from the list stRecord.
   • Percentage of the student
   • Marks in the fifth subject
   • Maximum marks of the student
   • Roll no. of the student
   • Change the name of the student from ‘Raman’ to ‘Raghav’

   Answer:

   • Percentage: stRecord[3]
   • Marks in the fifth subject: stRecord[2][4]
   • Maximum marks: max(stRecord[2])
   • Roll no.: stRecord[1]
   • Change name: stRecord[0] = 'Raghav'
   
   

Python Lists: Key Concepts for Class 11 NCERT 2025-26

Mastering Python lists is crucial for Class 11 Computer Science. This chapter teaches list creation, manipulation, and traversal, which form the basis of working with data sequences in Python.

Practicing NCERT-based exercises on list operations, slicing, and functions will help you confidently tackle questions in exams. Review example programs and code snippets for practical clarity.

Revise important functions like append(), extend(), and sort() for quick scoring. Consistent revision of list concepts with NCERT solutions ensures a strong foundation for your 2025-26 Computer Science exams.