A radioactive sample having an activity of has twice the number of nuclei as another…

PHYSICS · Single correct · A Level · Physics · Nuclear physics · Nuclear physics

Problem

A radioactive sample

S_1

having an activity of

5\,\mu\text{Ci}

has twice the number of nuclei as another sample

S_2

which has an activity of

10\,\mu\text{Ci}

. The half-lives of

S_1

and

S_2

can be (1) 20 yr and 5 yr, respectively (2) 20 yr and 10 yr, respectively (3) 10 yr each (4) 5 yr each