Question

The decay constant of a radioactive element is $1.5 \times 10^{- 9}$ per second. Its mean life in seconds will be.

• A. $1.5 \times 10^{9}$
• B. $4.62 \times 10^{8}$
• C. $6.67 \times 10^{8}$
• D. $10.35 \times 10^{8}$

Answer 1

Answer: (C)

$6.67 \times 10^{8}$

Answer 2

Mean life $= \frac{1}{\lambda} = 6.67 \times 10^{8}sec.$