The activity of a radioactive sample falls from to in 30 minutes

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

Problem

The activity of a radioactive sample falls from

700 \text{ s}^{-1}

500 \text{ s}^{-1}

in 30 minutes. Its half life is close to: (1) 72 min (2) 62 min (3) 66 min (4) 52 min