# How many wave cycles exist in a photon?

When we say a photon is a packet of energy with frequency of f, it means it consists of at least one electromagnetic wave cycle (otherwise we can not measure its wavelength).

Is there any experiment or theory that shows how many wave cycles exist in each photon? I am asking because besides the frequency, this number also can affect the energy of the photon (a photon with two cycles should have two times higher energy than a photon with just one cycle, while they both have the same frequency and wavelengths). This is a little paradoxical to me, because as far as I know the energy of photon only depends on its frequency.

• This must be a duplicate of some other question, but I can't find it. – garyp Sep 10 '16 at 20:55