Question

For a radioactive material, half-life is 10 minutes. If initially there are 600 number of nuclei, the time taken (in minutes) for the disintegration of 450 nuclei is

(a) 20

(b) 10

(c) 30

(d) 15

Answer 1

The correct option is (a) 20.

Explanation:

Number of nuclei remaining, 

N = 600 - 450 = 150 

According to the law of radioactive decay,