Question

7.A radioactive nucleus A with a half life T, decays into a nucleus B. At t=0, there is no nucleus B. At sometime t, the ratio of the number of B to that of A is 0.3. Then, t is given by : (1) t = T/ log (1.3) (2) t = (T/2)*(log 2/log 1.3) (3) t = T*(log 1.3/log 2) (4) t=T log (1.3)

Answer 1