Question

$T$ is the half life period and $T_a$ is the average life of a radioactive substance. Which of the following statement is correct ?

• A. $T$> $T_a$
• B. $T$ is about 69% of $T_a$
• C. $T$ is inversely proportional to $T_a$
• D. $T$ and $T_a$ both are directly proportional to radioactive decay constant.

Answer 1

Answer: (B)

$T$ is about 69% of $T_a$

Answer 2

$T = \frac{0.693}{\lambda}$ and $\lambda = 1 / T_a$. Hence $T = 0.693 \, T_a$