Question

Mean life of a radioactive sample is $100$s. Then its half-life(in minutes) is.

• A. $0.693$
• B. $1$
• C. ${10}^{-4}$
• D. $1.155$

Answer 1

The correct option is D $1.155$

Mean life $=\frac{1}{\lambda }=100So,\lambda =\frac{1}{100}se{c}^{-1}\lambda =\frac{0.693}{t_{1/2}}\frac{1}{100}{sec}^{-1}=\frac{0.693}{t_{1/2}}{t}_{1/2}=0.693\times 100sec{t}_{1/2}=\frac{0.693\times 100}{60}min{t}_{1/2}=1.155min$