A radioactive material whose half life period is 2 years weighs 1 ~g and is stored in the laboratory for 4 years. Then the amount of remaining radioactive material is

Step-by-step solution

Half life, T _ 1 / 2 =2 year Quantity of substance, N ₀=1 ~g Using law of radio activity, N = N ₀ e ^ - t Decay constant, = 0.693 ~T _ 1 / 2 aligned & = 0.693 2 =0.346 & =0.35 per year & Thus, N =1 e ^ -0.35 4 =0.25 ~g aligned