What is the momentum of a photon of energy 1 MeV in kg m/s ?

Options

A. `5xx10^(-24)`
B. `5.1xx10^(-22)`
C. `7.5xx10^(-19)`
D. `12xx10^(8)`

Answer

B

Explanation

For a photon `E=mc^(2)=(mc)xxc=("momentum")xx(c)`
`:.` Momentum (mc)`=(E)/(c)=(1"MeV")/(3xx10^(8))`
`=(1.6xx10^(-19)xx10^(6))/(3xx10^(8))`
`=5.1xx10^(-22)` kg m/s