Question

1. The set containing no element in it is called​

Answer 1

Empty set

Explanation:

The set containing no element in it is called​ an empty set.

One of the example of an empty set is as follows :

A = {x : x² = 4, x is odd}

In this case, if x = 2, then x² = (2)² = 4

There is no number other than 2 whose square is equal to 4.

Hence, this is an empty set.