Regular Grammar

Question 1
Marks : +2 | -2
Pass Ratio : 100%
A language is regular if and only if?
Accepted by DFA
Accepted by PDA
Accepted by LBA
Accepted by Turing machine
Explanation:
All of above machine can accept regular language but all string accepted by machine is regular only for DFA.
Question 2
Marks : +2 | -2
Pass Ratio : 100%
Which of the following is true?
All subsets of a regular set are always regular
All finite subsets of non-regular set are always regular
Union of two non regular set of language is not regular
Infinite times union of finite set is always regular
Explanation:
None.
Question 3
Marks : +2 | -2
Pass Ratio : 100%
How many strings of length less than 4 contains the language described by the regular expression (x+y)*y(a+ab)*?
7
10
12
11
Explanation:
String of length 0 = 1
Question 4
Marks : +2 | -2
Pass Ratio : 100%
L and ~L are recursive enumerable then L is?
Regular
Context free
Context sensitive
Recursive
Explanation:
If L is recursive enumerable and its complement too if and only if L is recursive.
Question 5
Marks : +2 | -2
Pass Ratio : 100%
Let the class of language accepted by finite state machine be L1 and the class of languages represented by regular expressions be L2 then?
L1<l2
L1>=L2
L1 U L2 = .*
L1=L2
Explanation:
Finite state machine and regular expression have same power to express a language.
Question 6
Marks : +2 | -2
Pass Ratio : 100%
Regular expression is __________
Type 0 language
Type 1 language
Type 2 language
Type 3 language
Explanation:
According to the Chomsky hierarchy.
Question 7
Marks : +2 | -2
Pass Ratio : 100%
Which of the following is not a regular expression?
[(a+b)*-(aa+bb)]*
[(0+1)-(0b+a1)*(a+b)]*
(01+11+10)*
(1+2+0)*(1+2)*
Explanation:
Except [(0+1)-(0b+a1)*(a+b)]* all are regular expression.
Question 8
Marks : +2 | -2
Pass Ratio : 100%
Which of the following is true?
(01)*0 = 0(10)*
(0+1)*0(0+1)*1(0+1) = (0+1)*01(0+1)*
(0+1)*01(0+1)*+1*0* = (0+1)*
All of the mentioned
Explanation:
None.
Question 9
Marks : +2 | -2
Pass Ratio : 100%
What is Regular grammar?
Context free grammar
Non context free grammar
English grammar
None of the mentioned
Explanation:
Regular grammar is subset of context free grammar.
Question 10
Marks : +2 | -2
Pass Ratio : 100%
Regular expressions are closed under _____________
Union
Intersection
Kleene star
All of the mentioned
Explanation:
According to the definition of regular expression.