Question

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

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

Answer 1

The correct option is C $0.16$

Remaining activity $=0.01M$ after $24h$

Remaining activity $=$ Initial activity $\times {\left(\frac{1}{2}\right)}^n$

Used half-life time $\left(n\right)=\frac{Totaltime}{t_{1/2}}=\frac{24}{6}=4$

So, $0.01=$ Initial activity $\times {\left(\frac{1}{2}\right)}^4$

Initial activity $=0.01\times 16=0.16M$