A piece of radioactive material contains 1000 atmos. If its half -life is 20seconds, the time taken for 125 atoms to remain is
A
20 seconds
B
40 seconds
C
80 seconds
D
60 seconds
Verified Correct Answer: D.
Physical Principles & Numerical Solution
1000 → 500 → 250 → 125
20 + 20 + 20 = 60s
Source: Myschool Past Questions Archive (Record #27424)