UGC NET COMPUTER SCIENCE:DISCRETE STRUCTURES,NETWORKS,DIGITAL LOGICS IMPORTANT SOLVED MCQ

 DISCRETE STRUCTURES, NETWORKS, DIGITAL LOGIC FUNDAMENTALS BASICS FOR UGC NET COMPUTER SCIENCE

1. What is a set.
A set can be defined as an unordered collection of distinct objects.

Example: A={3,6,2,8,7} can be called as a "set"

2. What is the difference between a partial order relation and equivalence relation.
A relation that is Reflexive, Antisymmetric, Transitive is said to be a Partial order  relation.
A relation which is Reflexive, Symmetric and Transitive is called as an Equivalence relation.
 Shortcut: RAT=Partial order
                     RST=Equivalence

3. What is meant by negation.
Negation means the opposite of the given preposition.
Example:
The negation of the preposition 'A' is ~A.
The negation of True is False
The negation of False is True

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