One gram of a radiactive material having a half-life period of `2` years is kept in store for a duration of `4` years. Calculate how much of the material ramins uncahnged.

Answer

`0.25g`

Explanation

According to radioactive decay law, we have
`N =N_(0) 2^(-t//T)`
Here, we have `T=2 yr` and `t=4 yr`. Thus, we have
`N=N_(0) 2^(-4//2)=(N_(0))/(4)=(1)/(4) g`
Thus, after 4 years,`0.25 g` of the material will be left.