Question

If $\frac{3}{4}$ quantity of a radioactive substance decays in $2$ hrs, its half life would be:

• A. $1$ hour
• B. $45$ minutes
• C. $30$ minutes
• D. $15$ minutes

Answer 1

The correct option is C $30$ minutes

$-\ln \left(0.75\right)=120.kk=-\ln \left(0.75\right)/120.0$

So, $t_{1/2}=\frac{0.693}{k}=30min.$