Which one of the following is an example of empty set?

Question

Question

Answer 1

Concept:

The empty set is the unique set having no elements; the count of elements in a set is zero.

Calculation:

1. Set of all even prime number = {2}

So, its not empty set.

2. {x : x2 - 2 = 0 and x is a real number}

x = +√2 and - √2

Its not empty set.

3. {x : x is a natural number, x > 8 and simultaneously x < 12}

It is also non empty set.

4.{ x : x is a common point to any two parallel lines}

It is an empty set as parallel lines do not have a common point.

Hence, option (4) is correct.