Question

Half life of a Radioactive element is 100 years .What will be its average life ?

• A. $13.4years$
• B. $1.44years$
• C. $144years$
• D. None of these

Answer 1

The correct option is C $144years$

$\lambda =\frac{0.693}{t_{1/2}}$
$\Rightarrow Averagelife,\tau =\frac{1}{\lambda }=\frac{t_{1/2}}{0.693}=\frac{100}{0.693}=144$