Theory of Automata MCQs with Answers
Practice important Theory of Automata MCQs with answers and explanations.
Chapter: 4
Q61:
A regular expression defining strings of length 2, starting with a, is ______.
A. a*a
B. aa+ab
C. a*b
D. ab+ba
Correct Answer:
B
Chapter: 5
Q62:
Which language is accepted by a finite automaton starting with a symbol 'b'?
A. L1 = b(a + b)*
B. L2 = a(a + b)* + Λ
C. L = b(aa + bb)
D. L = b(aa + bb)(a + b)
Correct Answer:
A
Chapter: 5
Q63:
What is the regular expression for a language of strings over Σ = {a, b} starting with b?
A. (a+b)*a
B. b(a + b)*
C. (a + b)*(a + b)
D. b(aa + bb)
Correct Answer:
B
Chapter: 5
Q64:
In a transition diagram, the final state is represented by:
A. A single circle
B. A double circle
C. A dashed circle
D. An arrow before the state
Correct Answer:
B
Chapter: 5
Q65:
The language L1 defined by the regular expression a(a + b)* represents:
A. Strings starting with b
B. Strings starting with a
C. Strings ending in b
D. Strings containing an even number of a’s
Correct Answer:
B
Chapter: 5
Q66:
How is the initial state represented in a finite automaton?
A. A single circle
B. A dashed circle
C. An arrow pointing to the state
D. A double circle
Correct Answer:
C
Chapter: 5
Q67:
Which regular expression describes strings over Σ = {a, b} ending in a?
A. b(a + b)*
B. a(a + b)* + Λ
C. (a + b)*a
D. (a + b)*b
Correct Answer:
C
Chapter: 5
Q68:
The language of strings beginning and ending with the same letter can be expressed as:
A. a(a + b)* a + b(a + b)* b
B. (a+b)*(a+b)
C. (a + b)*(a + b)
D. aa + bb
Correct Answer:
A
Chapter: 5
Q69:
Which language is defined by the regular expression ((a + b) (a + b))*?
A. Strings of odd length
B. Strings of even length
C. Strings containing only 'a'
D. Strings starting with 'b'
Correct Answer:
B
Chapter: 5
Q70:
Fill in the blank: The language of strings ending in 'a' over Σ = {a, b} can be expressed by the regular expression _____.
A. b(a + b)*
B. (a + b)*a
C. (a + b)*
D. a(a + b)*
Correct Answer:
B
Chapter: 5
Q71:
Which of the following is true about the language of strings of even length?
A. It can be expressed by the regular expression ((a + b)(a + b))*
B. It starts with 'b'
C. It has only one final state
D. It is not regular
Correct Answer:
A
Chapter: 5
Q72:
What is the regular expression for a language of strings of length two, starting with 'a'?
A. aa + ab
B. ba + bb
C. (a + b)*(a + b)
D. a(a + b)*
Correct Answer:
A
Chapter: 5
Q73:
The finite automaton accepting a language over Σ = {a, b}, where strings start with 'a' can be expressed by:
A. (a+b)*
B. a(a + b)*
C. aa + bb
D. b(a + b)*
Correct Answer:
B
Chapter: 5
Q74:
Fill in the blank: The language of strings of length two or more, starting and ending with the same letter, is represented by the regular expression _____.
A. a(a + b)* a + b(a + b)* b
B. (a + b)*
C. aa + bb
D. b(a + b)*
Correct Answer:
A
Chapter: 5
Q75:
The finite set of input letters in a finite automaton (FA) is called:
A. Input strings
B. Alphabet
C. Transition
D. State
Correct Answer:
B
Chapter: 5
Q76:
Which regular expression describes the language L of strings beginning and ending with 'a'?
A. a(a + b)* a
B. a(a + b)* + Λ
C. (a + b)*a
D. (a + b)(a + b)
Correct Answer:
A
Chapter: 6
Q77:
The language of strings starting and ending with different letters over Σ = {a, b} is expressed by:
A. a(a + b)*b
B. (a + b)*a
C. b(a + b)*
D. (a + b)*
Correct Answer:
A
Chapter: 6
Q78:
What is the regular expression for the language of all non-empty strings over Σ = {a, b}?
A. (a + b)*
B. (a + b)+
C. a(a + b)
D. b(a + b)
Correct Answer:
B
Chapter: 6
Q79:
The finite automaton that does not accept any string, including the null string, is an example of:
A. An empty FA
B. A disconnected FA
C. A non-final FA
D. A null FA
Correct Answer:
B
Chapter: 6
Q80:
Two finite automata (FAs) are considered equivalent if they:
A. Have the same number of states
B. Accept the same language
C. Start and end in the same state
D. Both accept the null string
Correct Answer:
B