No. Of T 1/2 Fraction of Activity Left A(t)/A 0 0 1 1 1/2 1 2 1/2 2 3 3 1/2 3 2 = 2x2x2 = 8 n 1/2 n n A(t) = A /2 ; n = t/T 1/2 ; n = no. of half-lives 0 37