There is a stream of neutrons with kinetic energy of 0.0327 eV. If half life of neutrons is 700s, what fraction of neutrons will decay before they travel a distance of 10m? Take mass of neutron =`1.675xx10^(-27)kg.`

Answer

4

Explanation

`v=sqrt((2E)/(m))=2500 m//s`
Time taken to cover `10 m` distance,
`Delta t=(10)/(2500)=4xx10^(-3)s`
Fraction of neutrons decayed in time `Delta t` is `(Delta N)/(N)=(0.693)/(T_(1//2))Delta t ~~ 4xx10^(-6)`