Question

A plane electromagnetic wave is incident on a material surface. The wave delivers momentum p and energy E.

Options

• p = 0, E ≠ 0

• p ≠ 0, E = 0

• p ≠ 0, E ≠ 0

• p = 0, E = 0

Answer 1

p ≠ 0, E ≠ 0.

When an electromagnetic wave strikes a material surface, it transports the momentum, as well as the energy, to the surface. The striking electromagnetic wave exerts pressure on the surface. The total energy transferred to the surface by the electromagnetic wave is given by E = pc. Therefore, ​p ≠ 0, E ≠ 0.