The speed of electromagnetic wave in vacuum

Options

A. increases as we move from `gamma-` rays waves
B. decreases as we move from `gamma-` rays to radio waves
C. is same for all of them
D. None of these

Answer

C

Explanation

Incident momentum, `p=(E)/(c)`
For perfectly reflecting surface with normal incidence
`Deltap=2p=(2E)/(c)" "F=(Deltap)/(Deltat)=(2E)/(ct)" "P=(F)/(A)=(2E)/(ctA)`