Question

A human body required the $0.01\, M$ activity of radioactive substance after $24\, h$. Half-life of radioactive substanu is $6\, h$. Then injection of maximum activity of radioactive substance that can be injected

• A. 0.08
• B. 0.04
• C. 0.16
• D. 0.32

Answer 1

Answer: (C)

Remaining activity $= 0.01\, M$ after $24\, h$
Remaining activity = Initial activity $\times\left(\frac{1}{2}\right)^{n}$
Used half- life time ( $n$ )
$=\frac{\text { Total time }}{T_{1 / 2}}=\frac{24}{6}=4$
So, $0.01=$ Initial activity $\times\left(\frac{1}{2}\right)^{4}$
Initial activity $=0.01 \times 16=0.16$