How many elements has P(A), if A = Φ? Answer Φ is an empty or null set so it doesn’t have any element. So number of element n = 0 Number of elements in a power set n[P(A)] = 2n plug n = 0 we get n[P(A)] = 20 = 1 used formula [a0 =1] Hence, P(A) has one element.
