The half-life of `.^215At` is `100mus`. The time taken for the activity of a sample of `.^215At` to decay to `1/16th` of its initial value is

Options

A. `400 mu s`
B. `6.3 mu s`
C. `40 mu s`
D. `300 mu s`

Answer

a

Explanation

`(1)/(16)=(1)/(2^(t/100))`
or `(1)/(2^(4))=(1)/(2^(t//100)) =4 =(t)/(100)`
or `t=400 m u s`.