A radioactive substance contains 10, 000 nuclei and its half - life period is 20 days.The number of nuclei present at the end of 10 days is

Options

A. 7070
B. 9000
C. 8000
D. 7500

Answer

A

Explanation

`(N)/(N_(0)) = ((1)/(2))^(t/T)` or `(N)/(10000) = ((1)/(2))^(10/20)` or `N = (10000 xx 1)/(sqrt2) = (10000)/(1.414) = 7070`.