It is observerd that only `0.39%` of the original radioactive sample remains undecayed after eight hours. Hence,

Options

A. the half-life of that substance is `1h`
B. the mean-life of the substance is `[1//(log2)]h`
C. decay constant of the substance is `(log2)h^(-1)`
D. if the number of radioactive nuclei of the this substance at a given instant is `10`, then the number left after `30 min` would be `7.5`

Answer

a,b,c

Explanation

Use `(N)/(N_(0)) =e^(-lambda t)`.