Question

Three - fourths of the active nuclei present in a radioactive sample decay in $\frac{3}{4}$ s.The half life of the sample is -

• A. 1 s
• B. $\frac{1}{2}s$
• C. $\frac{3}{4}s$
• D. $\frac{3}{8}s$

Answer 1

The correct option is D

$\frac{3}{8}s$

$\frac{N}{N_0}=(\frac{1}{2}{)}^{\frac{t}{T}}=\frac{1}{4}\frac{t}{T}=2orT=\frac{t}{2}=\frac{3}{4\times 2}=\frac{3}{8}S.$