Computer Science MCQs with Answers – CS MCQ Questions for IT students who are preparing for academic and competitive exams in 2023.

## Computer Science MCQs with Answers

1. A set which contains a single element is called a ……..

A) Singleton

B) One set

C) Proper set

D) Improper set

Ans. A) Singleton

2. The set of all subsets of A is called

A) Improper set of A

B) Proper set of A

C) Power set of A

D) Subset of A

Ans. C) Power set of A

3. The sequence 1, 4, 16, 64, ……… can be explicitly be defined by the formula

A) f(n) = 4n

B) f(n) = 4n

C) f(n) = n4

D) f(n) = 4 + n

Ans. B) f(n) = 4n

4. The value of 5! recursively is ……..

A) 125

B) 130

C) 110

D) 120

Ans. D) 120

5. State true (T) or false (F)

In a transition graph

(i) The final state, q1 is represented by two concentric circles.

(ii) The directed edges from the initial state to the final state are labelled as input/output.

A) (i) T (ii) F

B) (i) F (ii) T

C) (i) T (ii) T

D) (i) F (ii) F

Ans. C) (i) T (ii) T

6. State true (T) or false (F)

(i) When the input to a Moore machine is Ú, the output is l(q0).

(ii) In a Moore machine D represents the output alphabet.

A) (i) F (ii) T

B) (i) T (ii) F

C) (i) T (ii) T

D) (i) F (ii) F

Ans. A) (i) F (ii) T

7. If there is more than one edge associated with a given pair of vertices, then these edges are called ………

A) loop

B) Combined edges

C) lines

D) Parallel edges

Ans. D) Parallel edges

8. Graphs containing either parallel edges or loops is referred as ……..

A) Pendant graph

B) General Graph

C) infinite graph

D) finite graph

Ans. B) General Graph

9. A …… consists of a finite set of rules or productions which specify the syntax of the language.

A) Tree

B) Automata

C) Roots

D) Grammar

Ans. D) Grammar

10. The ……. of a string is the number of symbols in the string.

A) Structure

B) Graph

C) length

D) finite graph

Ans. C) length

11. An automaton system in which the output depends only on the present input is called a ………

A) Mealy machine

B) Moore machine

C) Dot machine

D) DF machine

Ans. B) Moore machine

12. The machine which has a finite number of states is called a …….

A) Finite automata

B) Finite control

C) Deterministic finite machine

D) finite graph

Ans. C) Deterministic finite machine

13. A string is a sequence of symbols obtained from ……

A) £

B) ¥

C) å

D) d

Ans. C) å

14. Digital computers are ……

A) automata controlled

B) Finite controlled

C) Deterministic machines

D) finite graph-structured

Ans. C) Deterministic machines

15. A DFA is a —— tuple

A) 4

B) 5

C) 3

D) 2

Ans. B) 5

16. A DFA is ………

A) easy to construct

B) difficult to construct

C) not constructable

D) only being imagined

Ans. B) difficult to construct

17. ……. are used to represent a set of strings and include symbols that are arranged using certain syntax rules.

A) irregular expressions

B) normal expressions

C) regular expressions

D) abnormal expressions

Ans. C) regular expressions

18. The union of two regular expressions is a ………

A) irregular expression

B) regular expression

C) null set

D) matrix

Ans. B) regular expression

19. If L1 and L2 are regular, then the regular language is closed under ………

A) Multiplication

B) division

C) addition

D) complementation

Ans. D) complementation

20. Let å and G be the set of alphabets, then the function f: å®G* is called as ………

A) Isomorphism

B) endomorphism

C) homomorphism

D) epimorphism

Ans. C) homomorphism

21. The language for the grammar G = (V_{T} {0,1}, V_{N} = {S },F, S) where the set of productions F: S®11S, S®0 is

A) L(G) = {0, 000, 11000, 1111110,……..}

B) L(G) = {0, 110, 10000, 1111110,……..}

C) L(G) = {0, 110, 11110, 1110000,……..}

D) L(G) = {0, 110, 11110, 1111110,……..}

Ans. D) L(G) = {0, 110, 11110, 1111110,……..}

22. A …….. is an ordered tree in which each vertex is labelled with the left sides of a product and in which the children of a vertex represents its corresponding right sides.

A) complete tree

B) derivation tree

C) ordered tree

D) binary tree

Ans. B) derivation tree

23. …….. of a relation R is the smallest transitive relation containing R.

A) transitive closure

B) reflexive closure

C) symmetric closure

D) equivalence closure

Ans. A) transitive closure

24. The value of éeù =

A) 3

B) 2

C) 1

D) 0

Ans. A) 3

25. The …….. is the assumption that for some fixed but arbitrary n ³ 0, P holds for each natural number 0, 1, 2, …..,n

A) Hypothesis

B) Induction hypothesis

C) Alternate hypothesis

D) Principal hypothesis

Ans. B) Induction hypothesis

26. A connected graph with n vertices and n – 1 edge is a ………

A) Forest

B) Branch

C) Tree

D) Leaf

Ans. C) Tree

27. If S = {a, b} then x = abab is a ……… on S

A) Alphabet

B) String

C) Letter

D) Grammar

Ans. B) String

28. The lexical analysis phase of a computer is often based on the ……… of a finite automaton.

A) Simulation

B) Certification

C) Simplification

D) Addition

Ans. A) Simulation

29. At regular intervals the automaton reads one symbol from the ………

A) Output tape

B) Input tape

C) Monitor

D) Initial tape

Ans. B) Input tape

30. The ……… is called finite control.

A) White box

B) Black box

C) Yellow box

D) Red box

Ans. B) Black box

31. All the edges of the transition graph are labelled as ………

A) Input

B) Output

C) Input/Output

D) Input transition.

Ans. C) Input/Output

32. If Q is the set of states, then the number of the set of subsets of Q is ………

A) 3^{Q
}B) 2^{Q
}C) 4^{Q
}D) 5^{Q
}Ans. B) 2^{Q}

33. The start state of MN is the start state of ……

A) N_{M
}B) M_{P
}C) M_{Q
}D) M_{D
}Ans. D) M_{D}

34. In the output l(q(t), x(t)), here q(t) is the ……

A) present state

B) present input

C) Mealy state

D) Moore state

Ans. A) present state

35. A ……. can be accepted both by deterministic as well as non-deterministic automata.

A) Irregular expression

B) Regular expression

C) Transit expression

D) Intransit expression

Ans. B) Regular expression

36. …….. is a regular expression denoting empty language.

A) Î

B) x

C) f

D) q

Ans. C) f

37. Let x, y Î å, here x + y represents the set ………

A) {x, y}

B) {x, y, z}

C) {y, z}

D) {x, z}

Ans. A) {x, y}

38. A set which is represented using a regular expression is known as a ………

A) Irregular set

B) Regular set

C) Empty set

D) Finite set

Ans. B) Regular set

39. If L1 and L2 are regular then L_{1} * denotes

A) Language

B) Irregular language

C) Regular Language

D) Grammar

Ans. C) Regular Language

40. AÈf =

A) f

B) A

C) N

D) ¥

Ans. B) A

41. A grammar G=(V_{N}, V_{T}, S, F) is said to be a regular grammar Û the grammar is

A) right regular

B) left regular

C) A) and B)

D) A) or B)

Ans. D) A) or B)

42. State true (T) or false (F)

(i) A Èf = {x /x Î A or x Îf} = A

(ii) A Çf = {x /x Î A and x Îf} = f

A) (i) T (ii) T

B) (i) F (ii) F

C) (i) T (ii) F

D) (i) F (ii) T

Ans. A) (i) T (ii) T

43. The G.C.D of (81, 36) is ………

A) 5

B) 9

C) 6

D) 4

Ans. B) 9

44. State true (T) or false (F)

(i) A grammar in which there are no restrictions on its productions is called a type-0 grammar.

(ii) A grammar that contains only productions of the form a®b where a ³ b is called a type-1 grammar.

A) (i) F (ii) T

B) (i) T (ii) F

C) (i) T (ii) T

D) (i) F (ii) F

Ans. B) (i) T (ii) F

45. For any finite set A, the cardinality of the power set of A is

A) 2^{n
}B) 2^{A
}C) 2^{n(A)
}D) 2

Ans. C) 2^{n(A)}

46. A binary tree is a tree in which no parent can have more than ………. children.

A) 0

B) 1

C) 3

D) 2

Ans. D) 2

47. State true (T) or false (F)

(i) The number of edges incident on a vertex v is called the degree of v.

(ii) The sum of the degrees of the vertices of a graph G is twice the number of vertices.

A) (i) T (ii) F

B) (i) F (ii) T

C) (i) T (ii) T

D) (i) F (ii) F

Ans. C) (i) T (ii) T

48. State true (T) or false (F)

(i) A vertex having no incident edge is called a vertex.

(ii) A vertex having degree one is called a pendant vertex.

A) (i) T (ii) F

B) (i) F (ii) T

C) (i) T (ii) T

D) (i) F (ii) F

Ans. B) (i) F (ii) T

49. State true (T) or false (F)

(i) A sentential form is any derivative of the unique non-terminal symbol S.

(ii) Language is a superset of all terminal strings over VT.

A) (i) T (ii) F

B) (i) F (ii) T

C) (i) T (ii) T

D) (i) F (ii) F

Ans. A) (i) T (ii) F

50. State whether true (T) or false (F)

A regular expression is recursively defined as follows

(i) f is a regular expression denoting an empty language.

(ii) a is a regular expression that indicates the language containing only

A) (i) T (ii) T

B) (i) T (ii) F

C) (i) F (ii) T

D) (i) F (ii) F

Ans. A) (i) T (ii) T