UGC NET COMPUTER SCIENCE - DISCRETE STRUCTURES MCQS FOR DEC 2013

                                                         Discrete Structures

(IMPORTANT QUESTION AND ANSWERS FOR COMPUTER SCIENCE PAPER-2 AND PAPER-3.)

1. Which of the following is tautology?

a.)x v y

b.)x v (~y)

c.)x v(~x)

d.)(x=<y)^(x<=y)

Ans.: c.)

Explanation: 

X		~X		X V(~X)
T		F		T
F		T		T

Tip: '~' denotes negation that is '1' means '0' and '0' means '1'

'V' means 'OR' operator.

Side note: Tautolgy means all the results should be True(T) or 1

2. Minimum number of individual shoes to be picked up from a dark room (containing 10 pair of shoes) if we have to get atleast one proper pair.

a.)3

b.)11

c.)10

d.)20

Ans.: b.)

Explanation of logic: There are 10 pair of shoes.

A single proper matching pair can be found out only when we pick the 11th shoe because till 10th shoe we cannot be very sure that we will get the right pair. But the 11th shoe that we take will definitely let us match the right pair surely. (LOGICAL REASONING QUESTION)

Note: May be asked in interviews too.

3. Circle has how many vertices?

a.) No vetices

b.) 2 vertex

c.) 5 vertex

d.) Infinite vertices

Ans.: d.)

Note: A simple but logic question.

You can mark as much vertices as possible on a circle.

Example:

4. The logic of pumping lemma is and example of

a.)Recursion

b.) Divide and conquer rule

c.) Pigeon hole principle

d.) Iteration

Ans.: c.)

5. An undirected graph possesses an eulerian circuit only if it is connected and its vertices are

a.) All of even degree

b.) All of odd degree

c.) of any degree

d.) even in number

Ans.: a.)

6. 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.)

7. The number of edges in a connected graph with 'n' vertices is

a.) n-1

b.) n(n-1)/2

c.) n^2

d.) 2n-1

Ans.: a.)

8. A graph G           has

                     4,5

a.) 4 edges

b.) 5 edges

c.) 20 edges

d.) 15 edges

Ans.: c.)

Logic: Number of edges in Graph G(m,n)=m*n

9. A self complemented,distributed lattice is

a.) Boolean algebra

b.) Modular lattice

c.) Complete lattice

d.) Self dual lattice.

Ans.: a.)

10. A graph with all nodes of equal importance is called as

a.) Complete graph

b.) Regular graph

c.) Non regular graph

d.) Multigraph

Ans.: b.) 

11. A partial ordered relation is transitive, reflexive and

a.) bisymmetric

b.) antisymmetric

c.) antireflexive

d.) asymmetric

Ans.: b.)

12. If n is an integer, and n^2 is odd then 'n' is

a.) even

b.) odd

c.) even or odd

d.) prime

Ans.: b.)

Reason:

1.) Let n be 7 then,

n^2=49 

2.) Let n be 9 then,

n^2=81

In both cases, the result is an odd number 

Therefore, answer is odd.

Read another article on discrete structures:
http://netcompsci.blogspot.in/2013/09/discrete-structures-solved-mcqs-for-ugc.html

Recommend my blog to your friends.

Comments are most welcome.

Feel free to ask doubts.

Wish you all the best for the forthcoming exam.

Quote: "Practice makes a man the BEST".