The activity of a radioactive sample falls from $700 \mathrm {~s} ^ { - 1 }$ to $500 \mathrm {~s} ^ { - 1 }$ in 30 minutes. Its half life is close to: (1) 72 min (2) 62 min (3) 66 min (4) 52 min
The activity of a radioactive sample falls from $700 \mathrm {~s} ^ { - 1 }$ to $500 \mathrm {~s} ^ { - 1 }$ in 30 minutes. Its half life is close to:\\
(1) 72 min\\
(2) 62 min\\
(3) 66 min\\
(4) 52 min