Question

The radioactive decay rate of a radioactive element is found to be ${10}^3$ disintegrations / second at a certain time. If the half life of the element is one second, the decay rate after one second is x disintegrations per sec and after three seconds is y disintegrations per sec. Then y/x =

Answer 1

Decay rate at $t=0$ is $1000$Hz.

at $t=1=\frac{1000}{2^1}=500$/sec.

at $t=3=\frac{1000}{2^3}=125$/sec.