a light with frequency 'v' can't excite electrons from a metal surface if the threshold frequency of the metal is greater than the frequency of the wave( the light,electromagnetic radiation)so why don't the energies of the photons add up together and then excite the electron in the surface of...
what is the literal meaning of vector product? how could two vectors perpendicular to each other form a new vector which is totally out of their plane how is that possible? can we prove it mathematically as well as logically?