`n` photons of wavelength `lambda` are absorbed by a black body of mass `m` . The momentum gained by the body is

Options

A. `(h)/(m lambda)`
B. `(m n h)/(lambda)`
C. `(nh)/(m lambda)`
D. `(nh)/(lambda)`

Answer

D

Explanation

Energy of n photons , `E = (nhc)/(lambda)`
Momentum gained by the body `p = (E)/(c) = (nhc)/(lambda c) = (nh)/(lambda)`