How many elements has the Power set of A ,if A is an empty set ?

what is empty set?

No.of elements in Power set

Define empty set .

Which of the following cannot be the number of elements in the power set of any finite set ?

If the number of elements in the power set of set A is 128 then find the number of elements in the set A .

Two finite sets have m and n elements.The number of elements is the power set of first set is 48 more than the power set of second set.Then (m,n)=