Question

A radioactive sample decays 7/8 times its original quantity in 15 minutes. The half-life of the sample is

• A. 5 min
• B. 7.5 min
• C. 15 min
• D. 30 min

Answer 1

Answer: (A)

5 min

Answer 2

Remaining = $\frac{1}{8}$

$3t_{1/2}=15 min$

⇒ $t_{1/2}=5 min$