Question

The half life of a radioactive element which has only $\frac{1}{32}$ of its original mass left after a lapse of 60 days is.

• A. 12 days
• B. 32 days
• C. 60 days
• D. 64 days

Answer 1

Answer: (A)

12 days

Answer 2

$\frac{N_{0}}{32} = N_{0}\left( \frac{1}{2} \right)^{60/T} \Rightarrow 5 = \frac{60}{T} \Rightarrow T = 12$days.