Many unstable nuclie can decay spontaneously to a nucleus of lower mass but differnet combination of nucleons. The process of spontaneous emission of radiation is called radioactivity substance.
Radioactive decay is a statistical process. Radiaactivity is independent of all external conditions. The number of decays per unit time or decay rate is called activity. Activity exponentially decrease with time. Mean lifetime is always greater than half-life time.
n number of `alpha`-particels per second are being emitted by B atoms of a radioactive element. The half-life of element will be

Options

A. `(n)/(N) s`
B. `(N)/(n )s`
C. `0693 (N)/(n) s`
D. `0.693 (n)/(N) s`

Answer

c

Explanation

`A=(dN)/(dt)=lambda N, n=almbda N`
`n=(0.693)/(T) N, T=(0.693N)/(n)`.