This set of Automata Theory Multiple Choice Questions & Answers (MCQs) focuses on “Regular Language & Expression”.
1. How many strings of length less than 4 contains the language described by the regular expression (x+y)*y(a+ab)*?
Explanation : string of length 0 = 1
string of length 1 = 4
string of length 2 = 3
string of length 3 = 3
2. Which of the following is true?
a) (01)*0 = 0(10)*
b) (0+1)*0(0+1)*1(0+1) = (0+1)*01(0+1)*
c) (0+1)*01(0+1)*+1*0* = (0+1)*
d) All of the mentioned
Explaination : None.
3. A language is regular if and only if
a) accepted by DFA
b) accepted by PDA
c) accepted by LBA
d) accepted by Turing machine
Explanation : All of above machine can accept regular language but all string accepted by machine is regular only for DFA.
4. Regular grammar is
a) context free grammar
b) non context free grammar
c) english grammar
d) none of the mentioned
Explanation : Regular grammar is subset of context free grammar.
5. Let the class of language accepted by finite state machine be L1 and the class of languages represented by regular expressions be L2 then 6. Which of the following is not a regular expression? 7. Regular expression are 8. Which of the following is true? 9. L and ~L are recursive enumerable then L is 10. Regular expressions are closed under Sanfoundry Global Education & Learning Series – Automata Theory.
c) L1 U L2 = .*
Explanation : Finite state machine and regular expression have same power to express a language.
Explanation : Except b all are regular expression*.
a) Type 0 language
b) Type 1 language
c) Type 2 language
d) Type 3 language
Explanation : According to Chomsky hierarchy .
a) Every subset of a regular set is regular
b) Every finite subset of non-regular set is regular
c) The union of two non regular set is not regular
d) Infinite union of finite set is regular
Explanation : None.
b) Context free
c) Context sensitive
Explanation :If L is recursive enumerable and its complement too if and only if L is recursive.
c) Kleen star
d) All of the mentioned
Explanation : According to definition of regular expression.
To practice all areas of Automata Theory, here is complete set of 1000+ Multiple Choice Questions and Answers.
6. Which of the following is not a regular expression?
7. Regular expression are
8. Which of the following is true?
9. L and ~L are recursive enumerable then L is
10. Regular expressions are closed under
Sanfoundry Global Education & Learning Series – Automata Theory.