UGC NET Computer Science

Paper II

December 2006

1.   Which of the regular expressions corresponds to this grammar ?

S → AB / AS, A → a / aA, B → b

(A) aa*b+          

(B) aa*b

(C) (ab)*            

(D) a(ab)*

Ans: (B)


2. The proposition ~q∨p is equivalent to:







3. The number of edges in a complete graph with N vertices is equal to:

(A) N(N−1)       

(B) 2N−1

(C) N−1             

(D) N(N−1)/2

Ans: (D)


4. Which of the following is not true ?


(B) A−B = A∩~B





5. If (a2−b2) is a prime number where a and bϵN, then:

(A) a2−b2 = 3                

(B) a2−b2 = a−b

(C) a2−b2 = a+b            

(D) a2−b2 = 5

Ans: (C)


6. The hexadecimal equivalent of (10111)2×(1110)2 is:

(A) 150              

(B) 241

(C) 142             

(D) 101011110

Ans: (C)


7. An example of a self complementing code is:

(A) 8421 code              

(B) Gray code

(C) Excess-3 code      

(D) 7421 code

Ans: (C)


8. A sum of products expression can be implemented with……………logic gates.

(A) AND – OR             


(C) AND – NOT           

(D) OR – AND

Ans: (A)


9. The characteristic equation of the D flip-flop is:

(A) Qn+1 = D      

(B) Q = D

(C) Q = 1           

(D) Q = 0

Ans: (A)


10. Which of the following logic is the fastest ?

(A) RTL             

(B) ECL         

(C) HTL         


Ans: (B)


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