UGC NET Computer Science Solved Mcqs Paper II December 2004 - Part 1

1.       AVA = A is called:

(A) Identity law             (B) De Morgan’s law

(C) Idempotent law      (D) Complement law

Answer: C

2.       If f(x) =x+1 and g(x)=x+3 then fofofof is:

(A) g       (B) g+1

(C) g⁴     (D) None of the above

Answer: B

Explanation:

If f(x)=x+1 and g(x)=x+3, then fog(x)=x+4 and gof(x)=x+4

fof(x)=x+2, fofof(x)=x+3 and fofofof(x)=x+4.=x+3+1=g+1

3.       The context-free languages are closed for:

(i) Intersection                          (ii) Union

(iii) Complementation             (iv) Kleene Star

then

(A) (i) and (iv)               (B) (i) and (iii)

(C) (ii) and (iv)              (D) (ii) and (iii)

Answer: C

4.       The following lists are the degrees of all the vertices of a graph:

(i) 1, 2, 3, 4, 5                (ii) 3, 4, 5, 6, 7

(iii) 1, 4, 5, 8, 6              (iv) 3, 4, 5, 6

then, which of the above sequences are graphic?

(A) (i) and (ii)   

(B) (iii) and (iv)

(C) (iii) and (ii) 

(D) (ii) and (iv)

Answer: B

Explanation:

Rest can't be graphs as the number of vertices with odd degree in a graph should be even.

In list (i), number of vertices with odd degree is 3.

In list (ii), number of vertices with odd degree is 3.

In list (iii), number of vertices with odd degree is 2.

In list (iv), number of vertices with odd degree is 2.

5.       If I_m denotes the set of integers modulo m, then the following are fields with respect to the operations of addition modulo m and multiplication modulo m:

(i) Z₂₃      (ii) Z₂₉

(iii) Z₃₁    (iv) Z₃₃

Then

(A) (i) only                                

(B) (i) and (ii) only

(C) (i), (ii) and (iii) only           

(D) (i), (ii), (iii) and (iv)

Answer: C

6.       An example of a binary number which is equal to its 2’s complement is:

(A) 1100                        (B) 1001

(C) 1000                        (D) 1111

Answer: C

7.       When a tri-state logic device is in the third state, then:

(A) it draws low current          

(B) it does not draw any current

(C) it draws very high current

(D) it presents a low impedance

Answer: D

8.       An example of a connective which is not associative is:

(A) AND             (B) OR

(C) EX-OR        (D) NAND

Answer: D

9.       Essential hazards may occur in:

(A) Combinational logic circuits

(B) Synchronous sequential logic circuits

(C) Asynchronous sequential logic circuits working in the fundamental mode

(D) Asynchronous sequential logic circuits working in the pulse mode

Answer: C

10.    The characteristic equation of a T flip-flop is:

(A) Q_n+1=TQ’_n + T’ Q_n              

(B) Q_n+1=T+Q_n

(C) Q_n+1=TQ_n                            

(D) Q_n+1= T’Q’_n

The symbols used have the usual meaning.

Answer: A

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