Question

What is the half-time of a radioactive sample (in minutes), if its mean life is 200 s?

(a) 0.69 min

(b) 2 min

(c) 2.57 min

(d) 2.31 min

I had been asked this question during an interview.

My doubt is from Nucleus topic in section Nucleus of Physics – Class 12

Answer 1

The correct answer is (d) 2.31 min

Explanation: T1/2 = 0.693t

T1/2 = 0.693 × 200s

T1/2 = \(\frac {138.6}{60}\) min

T1/2 = 2.31 minutes