Question

The probability that a certain radioactive atom would get disintegrated in a time equal to the mean life of the radioactive sample is:

• A. 0.37
• B. 0.63
• C. 0.50
• D. 0.67

Answer 1

The correct option is B

0.63

Required probability $P\left(t\right)=\frac{N_0(1-e^{-\lambda t})}{N_0}=1-e^{-\lambda \times \frac{1}{\lambda }}=1-e^{-1}\simeq 0.63$