250+ TOP MCQs on PDA-acceptance by Empty Stack and Answers

Automata Theory Multiple Choice Questions on “PDA-acceptance by Empty Stack”.

1. If two sets, R and T has no elements in common i.e. RÇT=Æ, then the sets are called
a) Complement
b) Union
c) Disjoint
d) Connected

Answer: c
Clarification: Two sets are called disjoint if they have no elements in common i.e. RÇT=Æ.

2. Which among the following is not a part of the Context free grammar tuple?
a) End symbol
b) Start symbol
c) Variable
d) Production

Answer: a
Clarification: The tuple definition of context free grammar is: (V, T, P, S) where V=set of variables, T=set of terminals, P=production, S= Starting Variable.

3. A context free grammar is a ___________
a) English grammar
b) Regular grammar
c) Context sensitive grammar
d) None of the mentioned

Answer: c
Clarification: Context free grammar is the set which belongs to the set of context free grammar. Similarly, Regular grammar is a set which belongs to the the set of Context free grammar.

4. The closure property of context free grammar includes :
a) Kleene
b) Concatenation
c) Union
d) All of the mentioned

Answer: d
Clarification: Context free grammars are closed under kleene operation, union and concatenation too.

5. Which of the following automata takes stack as auxiliary storage?
a) Finite automata
b) Push down automata
c) Turing machine
d) All of the mentioned

Answer: b
Clarification: Pushdown Automaton uses stack as an auxiliary storage for its operations. Turing machines use Queue for the same.

6. Which of the following automata takes queue as an auxiliary storage?
a) Finite automata
b) Push down automata
c) Turing machine
d) All of the mentioned

Answer: c
Clarification: Pushdown Automaton uses stack as an auxiliary storage for its operations. Turing machines use Queue for the same.

7. A context free grammar can be recognized by
a) Push down automata
b) 2 way linearly bounded automata
c) Both (a) and (b)
d) None of the mentioned

Answer: c
Clarification: A linearly bounded automata is a restricted non deterministic turing machine which is capable of accepting ant context free grammar.

8. A null production can be referred to as:
a) String
b) Symbol
c) Word
d) All of the mentioned

Answer: a
Clarification: Null production is always taken as a string in computational theory.

9. The context free grammar which generates a Regular Language is termed as:
a) Context Regular Grammar
b) Regular Grammar
c) Context Sensitive Grammar
d) None of the mentioned

Answer: b
Clarification: Regular grammar is a subset of Context free grammar. The CFGs which produces a language for which a finite automaton can be created is called Regular grammar.

10. NPDA stands for
a) Non-Deterministic Push Down Automata
b) Null-Push Down Automata
c) Nested Push Down Automata
d) All of the mentioned

Answer: a
Clarification: NPDA stands for non-deterministic push down automata whereas DPDA stands for deterministic push down automata.