`1 mg` gold undergoes decay with `2.7` days half-life period, amount left after `8.1` days is

Options

A. `0.91 mg`
B. `0.25 mg`
C. `0.5 mg`
D. `0.125 mg`

Answer

D

Explanation

(d) `N = N_0((1)/(2))^n rArr N = N_0 ((1)/(2))^(t//T_(1//2))`
`rArr N = 1 xx ((1)/(2))^((8.1)/(2.7)) = ((1)/(2))^3 = (1)/(8)`
`rArr N = (1)/(8) mg = 0.125 mg`.