if an electron has wavelength,does it also have colour?
Should energy of photon be called its Kinetic energy or internal energy?
In a photoelectric experiment,if photon is incident on a metal plate in one direction and photoelectron is
Only electromagnetic waves with wavelengths from 380 nm to 780 nm have colours that human eye can recognize. It's called visible spectrum. The electron wavelength is outside visible spectrum, hence no question of labeling it a colour. That would be same as asking what's the colour of radio waves?
It's just energy, it's all to it. When particles move at speeds comparable to the speed of light or to the value 3x108 m/s, kinetic energy is no longer given by mv2/2, and photon's rest mass is zero, it has no substructure, it's the elementary particle, so no question of internal energy. It might be appropriate to call it kinetic energy, if required.
Yes, law of conservation of momentum hold good. The free electron are in a continuous state of random motion.