A sample of cobalt-60 shows an activity of counts per second at

PHYSICS · Subjective · A Level · Physics · Nuclear physics · Nuclear physics

Problem

A sample of cobalt-60 shows an activity of

4000

counts per second at

t=0

. If its decay constant is

\lambda = 0.131\,\text{yr}^{-1}

, calculate its activity after

5

years (give your answer to the nearest whole count per second).