Physics

Problem

A sample contains equal numbers of nuclei of two isotopes,

A

and

B

. The half-life of

A

2\,\text{h}

, while that of

B

6\,\text{h}

. a. (i) Calculate the ratio

N_A:N_B

of the numbers of undecayed nuclei remaining after

6\,\text{h}

. b. (ii) Hence find the ratio of their activities

A_A:A_B

at that time.