State whether each of the following set is finite or infinite :

The set of letters in the English alphabet

In the following state whether $A=B$ or not :

$A=\{4,8,12,16\} ; B=\{8,4,16,18\}$

How many elements has $P(A),$ if $A=\varnothing ?$

Let $A=\{1,2,\{3,4\}, 5\} .$ Which of the following statements are incorrect and why ?

$\{ 3,4\}  \in A$

List all the elements of the following sers :

$A = \{ x:x$ is an odd natural number $\} $

Write down all the subsets of the following sets

$\{ a\} $