Theory of Automata MCQs with Answers
Practice important Theory of Automata MCQs with answers and explanations.
Multiple Choice Questions
Q31: The language of strings having at least one 'a' and one 'b' can be expressed by which of the following regular expressions?
- A: (a+b)*a(a+b)b(a+b)
- B: aba*
- C: aabb
- D: (a+b)a(a+b)
View Answer
A
Q32: How is a language with strings starting with 'aa' and ending with 'bb' expressed in regular expressions?
- A: aa(a+b)*bb
- B: abab*
- C: (a+b)aa(a+b)*
- D: a(a+b)*b
View Answer
A
Q33: What does the regular expression (a+b)* represent?
- A: Only strings with 'a' and 'b'
- B: Strings of 'a' and 'b'
- C: All possible strings of 'a' and 'b', including the null string
- D: Strings with at least two 'a's
View Answer
C
Q34: What is the base step in the recursive definition of Regular Expression?
- A: Every letter in Σ is an RE
- B: Λ is not an RE
- C: All words in Σ are not REs
- D: Every string of finite length is an RE
View Answer
A
Q35: Which regular expression generates all strings starting with 'a' and ending in 'b'?
- A: a(a+b)*b
- B: (a+b)*a
- C: aab
- D: b*(a+b)*
View Answer
A
Q36: What is the recursive step for creating a regular expression from two expressions r1 and r2?
- A: r1 + r2 is not a regular expression
- B: r1 r2 is a regular expression
- C: r1* is not a regular expression
- D: (r1)(r2) is not a regular expression
View Answer
B
Q37: Which of the following represents the language of strings with odd length in regular expressions?
- A: ((a+b)(a+b))*
- B: (a+b)((a+b)(a+b))*
- C: a(a+b)*b
- D: b*(a+b)*a
View Answer
B
Q38: Fill in the blank: The regular expression ______ represents the language with at least one 'a'.
- A: bab
- B: (a+b)a(a+b)
- C: (a+b)(a+b)*
- D: aabb
View Answer
B
Q39: Fill in the blank: The recursive definition of regular expressions allows the use of _______.
- A: r1 r2
- B: r1 + r2
- C: r1*
- D: All of the above
View Answer
D
Q40: Fill in the blank: The regular expression ______ defines a language where strings start with 'aa' and end with 'bb'.
- A: aa(a+b)*bb
- B: (a+b)*
- C: bbb
- D: aba
View Answer
A