Is e.m. Wave have momentum and …

The building units of the electromagnetic radiation is the photons. The photons are a bunch of waves confined in space and have quantized energy. The energy in a photon is proportional to its frequency and equals hf where h is the Planck constant. by observing the behavior of photons. it is found that in addition of energy it has momentum and consequently it has an effective mass or associated mass m. However the rest mass is zero because electromagnetic waves do not exist at rest. According to conservation of energy and mass, the energy has an equivalent mass according to the Einstein The energy E =m C^2= hC/ Lambda.. Then the momentum of the photon is equals mC. The experiments which demonstrate the particle duality of the photons is the photo electric effect where the photons collide with electrons which are tiny masses and knock them out of the material. In high energy electromagnetic radiation the momentum is relatively large and observable. Electromagnetic radiation behaves as waves in the transmission and as photons in interacting with the material