Question

The de - Broglie wavelength of a neutron in thermal equilibrium with heavy water at a temperature `T ("kelvin")` and mass `m`, is
A. `lambda=h/(sqrt(3mKT))`
B. `lambda=h/(sqrt(6mKT))`
C. `lambda=h/(sqrt(5mKT))`
D. `lambda=h/(sqrt(2mKT))`

Answer 1

Correct Answer - A
As `1/2mv^(2)=3/2kT :. mv^(2)=3kT`
or `m^(2)v^(2)=3mkT`
or `mv=sqrt(3mkT)`
`lambda=h/(mv)=h/(sqrt(3mkT))`