CUET PG Computer Science Practice Set 1

CUET PG Computer Science · 2026 · with answers and explanations

questions
30
Total marks
30
Duration
105 minutes
Negative marking
−0.25

Subjects: Aptitude (Reasoning) · Mathematics · Computer Science

Question 1

Aptitude (Reasoning) · 1 marks · −0.25

If "book" is called "pen", "pen" is called "table", and "table" is called "chair", what would you write with?

  1. A.Book
  2. B.Pen
  3. C.Table
  4. D.Chair

Correct answer: C

Explanation: The object originally called "pen" (a writing tool) is now renamed "table" in this code, so you write with what is now called "table".

Question 2

Aptitude (Reasoning) · 1 marks · −0.25

Statements: Some doctors are engineers. All engineers are teachers. Conclusion: Some doctors are teachers.

  1. A.Conclusion follows
  2. B.Conclusion does not follow
  3. C.Cannot be determined
  4. D.Conclusion is false

Correct answer: A

Explanation: Since some doctors are engineers and all engineers are teachers, those doctors who are engineers must also be teachers, so the conclusion validly follows.

Question 3

Aptitude (Reasoning) · 1 marks · −0.25

In the series 3, 9, 27, 81, ? — what is the next number and what pattern governs the series?

  1. A.162, arithmetic pattern
  2. B.243, geometric pattern
  3. C.200, arithmetic pattern
  4. D.225, geometric pattern

Correct answer: B

Explanation: Each term is obtained by multiplying the previous term by 3, forming a geometric progression: 81 × 3 = 243.

Question 4

Mathematics · 1 marks · −0.25

If |A| = 20, |B| = 15, and |A ∩ B| = 5, what is |A ∪ B|?

  1. A.30
  2. B.35
  3. C.25
  4. D.40

Correct answer: A

Explanation: |A ∪ B| = |A| + |B| − |A ∩ B| = 20 + 15 − 5 = 30.

Question 5

Mathematics · 1 marks · −0.25

In how many ways can 5 different books be arranged on a shelf?

  1. A.25
  2. B.60
  3. C.120
  4. D.100

Correct answer: C

Explanation: The number of arrangements of 5 distinct items is 5! = 120.

Question 6

Mathematics · 1 marks · −0.25

A relation R on set A = {1, 2, 3} is defined as R = {(1,1), (2,2), (3,3), (1,2), (2,1)}. Which properties does R have?

  1. A.Reflexive and symmetric but not transitive
  2. B.Reflexive, symmetric and transitive
  3. C.Only reflexive
  4. D.Only symmetric

Correct answer: B

Explanation: R contains all pairs (a,a), so it is reflexive; (1,2) and (2,1) both present, so it is symmetric; and (1,2) with (2,1) gives (1,1), which holds, satisfying transitivity. R is an equivalence relation.

Question 7

Mathematics · 1 marks · −0.25

A card is drawn from a standard deck of 52 cards. What is the probability that it is a king or a heart?

  1. A.4/13
  2. B.17/52
  3. C.1/13
  4. D.4/52

Correct answer: A

Explanation: P(king) = 4/52, P(heart) = 13/52, P(king and heart) = 1/52. P(king or heart) = 4/52 + 13/52 − 1/52 = 16/52 = 4/13.

Question 8

Mathematics · 1 marks · −0.25

The roots of the equation x² − 9 = 0 are:

  1. A.±3
  2. B.±9
  3. C.3 only
  4. D.−3 only

Correct answer: A

Explanation: x² = 9 ⟹ x = ±3.

Question 9

Mathematics · 1 marks · −0.25

If A = [[2, 3], [1, 4]], what is A⁻¹?

  1. A.(1/5)[[4, -3], [-1, 2]]
  2. B.(1/5)[[4, 3], [1, 2]]
  3. C.[[4, -3], [-1, 2]]
  4. D.(1/5)[[2, -3], [-1, 4]]

Correct answer: A

Explanation: det(A) = 2×4 − 3×1 = 5. For a 2×2 matrix [[a,b],[c,d]], the inverse is (1/det)[[d,-b],[-c,a]] = (1/5)[[4,-3],[-1,2]].

Question 10

Computer Science · 1 marks · −0.25

A sparse matrix is one in which:

  1. A.Most elements are zero
  2. B.Most elements are non-zero
  3. C.All elements are equal
  4. D.It is always square

Correct answer: A

Explanation: A sparse matrix has most of its elements as zero, so compact representations are used to save storage.

Question 11

Computer Science · 1 marks · −0.25

Which data structure follows the LIFO (Last In First Out) principle?

  1. A.Queue
  2. B.Stack
  3. C.Linked List
  4. D.Tree

Correct answer: B

Explanation: A stack is a LIFO structure; a queue is FIFO.

Question 12

Computer Science · 1 marks · −0.25

What is the time complexity to insert a node at the beginning of a singly linked list, given a pointer to the head?

  1. A.O(1)
  2. B.O(n)
  3. C.O(log n)
  4. D.O(n²)

Correct answer: A

Explanation: Insertion at the head only requires updating a constant number of pointers, so it is O(1).

Question 13

Computer Science · 1 marks · −0.25

In an AVL tree, an insertion causes a node's balance factor to become +2 while its left child's balance factor is −1. Which rotation is required to restore balance?

  1. A.Left-Right (LR) rotation
  2. B.Left-Left (LL) rotation
  3. C.Right-Right (RR) rotation
  4. D.Right-Left (RL) rotation

Correct answer: A

Explanation: A left-heavy imbalance (balance factor +2) with a right-heavy left subtree (child balance factor −1) requires a Left-Right (LR) double rotation.

Question 14

Computer Science · 1 marks · −0.25

Which graph traversal technique uses a queue data structure?

  1. A.Depth First Search
  2. B.Breadth First Search
  3. C.Both
  4. D.Neither

Correct answer: B

Explanation: Breadth First Search (BFS) uses a queue to explore nodes level by level; Depth First Search typically uses a stack or recursion.

Question 15

Computer Science · 1 marks · −0.25

Which sorting algorithm has the best average-case time complexity among the following?

  1. A.Bubble Sort
  2. B.Selection Sort
  3. C.Merge Sort
  4. D.Insertion Sort

Correct answer: C

Explanation: Merge Sort runs in O(n log n) on average, better than the O(n²) average case of Bubble Sort, Selection Sort, and Insertion Sort.

Question 16

Computer Science · 1 marks · −0.25

In hashing, when two different keys map to the same hash index, it is called:

  1. A.Overflow
  2. B.Collision
  3. C.Rehashing
  4. D.Clustering

Correct answer: B

Explanation: This situation, where two keys produce the same hash value, is called a collision.

Question 17

Computer Science · 1 marks · −0.25

Which of the following is a valid inter-process communication (IPC) mechanism?

  1. A.Shared memory
  2. B.Register allocation
  3. C.Cache coherence
  4. D.Paging

Correct answer: A

Explanation: Shared memory, along with pipes and message queues, is a standard IPC mechanism used for communication between processes.

Question 18

Computer Science · 1 marks · −0.25

Which CPU scheduling algorithm can lead to starvation of longer processes?

  1. A.First Come First Served
  2. B.Shortest Job First
  3. C.Round Robin
  4. D.FCFS with equal priority

Correct answer: B

Explanation: Shortest Job First (SJF) can starve longer processes indefinitely if a continuous stream of shorter jobs keeps arriving.

Question 19

Computer Science · 1 marks · −0.25

Which of the following is NOT one of the four necessary Coffman conditions for deadlock?

  1. A.Mutual exclusion
  2. B.Hold and wait
  3. C.Preemption
  4. D.Circular wait

Correct answer: C

Explanation: The actual condition is "no preemption" (resources cannot be forcibly taken away), not "preemption". The four conditions are mutual exclusion, hold and wait, no preemption, and circular wait.

Question 20

Computer Science · 1 marks · −0.25

Which page replacement algorithm can suffer from Belady's Anomaly?

  1. A.LRU
  2. B.Optimal
  3. C.FIFO
  4. D.LFU

Correct answer: C

Explanation: FIFO page replacement can exhibit Belady's Anomaly, where increasing the number of page frames results in more page faults, not fewer.

Question 21

Computer Science · 1 marks · −0.25

Which of the following is a standard method of disk space allocation in file systems?

  1. A.Contiguous allocation
  2. B.Round robin allocation
  3. C.Priority allocation
  4. D.FIFO allocation

Correct answer: A

Explanation: Contiguous, linked, and indexed allocation are the standard file allocation methods; the other options are not.

Question 22

Computer Science · 1 marks · −0.25

How many layers does the OSI reference model have?

  1. A.4
  2. B.5
  3. C.7
  4. D.6

Correct answer: C

Explanation: The OSI model has 7 layers: Physical, Data Link, Network, Transport, Session, Presentation, and Application.

Question 23

Computer Science · 1 marks · −0.25

Which access method does traditional Ethernet use to manage shared medium access?

  1. A.Token passing
  2. B.CSMA/CD
  3. C.Polling
  4. D.TDMA

Correct answer: B

Explanation: Ethernet traditionally uses CSMA/CD (Carrier Sense Multiple Access with Collision Detection); Token Ring uses token passing instead.

Question 24

Computer Science · 1 marks · −0.25

Which routing approach uses the Bellman-Ford algorithm to compute shortest paths?

  1. A.Link state routing
  2. B.Distance vector routing
  3. C.Flooding
  4. D.Static routing

Correct answer: B

Explanation: Distance vector routing protocols, such as RIP, use the Bellman-Ford algorithm to compute shortest paths.

Question 25

Computer Science · 1 marks · −0.25

What is the default subnet mask for a Class C IPv4 network?

  1. A.255.0.0.0
  2. B.255.255.0.0
  3. C.255.255.255.0
  4. D.255.255.255.255

Correct answer: C

Explanation: A Class C network's default subnet mask is 255.255.255.0, equivalent to a /24 prefix.

Question 26

Computer Science · 1 marks · −0.25

In RSA encryption, which of the following makes up the public key?

  1. A.The private exponent d
  2. B.The modulus n and public exponent e
  3. C.The prime factors p and q alone
  4. D.A symmetric key

Correct answer: B

Explanation: The RSA public key consists of the modulus n and the public exponent e; the private key uses the exponent d.

Question 27

Computer Science · 1 marks · −0.25

In an ER diagram, a relationship that associates at most one instance of an entity on each side is called:

  1. A.One-to-one
  2. B.Many-to-many
  3. C.One-to-many
  4. D.Many-to-one

Correct answer: A

Explanation: This is the definition of a one-to-one (1:1) relationship.

Question 28

Computer Science · 1 marks · −0.25

Which SQL join returns all rows from both tables, with NULLs where there is no match?

  1. A.INNER JOIN
  2. B.LEFT JOIN
  3. C.RIGHT JOIN
  4. D.FULL OUTER JOIN

Correct answer: D

Explanation: A FULL OUTER JOIN returns matched rows plus unmatched rows from both the left and right tables, filling unmatched columns with NULL.

Question 29

Computer Science · 1 marks · −0.25

A relation is in Third Normal Form (3NF) if it is in 2NF and:

  1. A.No non-prime attribute is transitively dependent on the primary key
  2. B.Every attribute is atomic
  3. C.It has no multivalued dependencies
  4. D.Every determinant is a candidate key

Correct answer: A

Explanation: 3NF requires that no non-prime attribute is transitively dependent on the primary key. "Every determinant is a candidate key" describes BCNF, a stricter form.

Question 30

Computer Science · 1 marks · −0.25

Which property of a database transaction ensures that partial transactions are never reflected in the database?

  1. A.Consistency
  2. B.Isolation
  3. C.Atomicity
  4. D.Durability

Correct answer: C

Explanation: Atomicity guarantees that a transaction is executed completely or not at all, so partial effects are never visible.

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