# Relation of energy to amplitude & frequency

Energy of a wave is given by the planck relation, which should be proportional to its frequency.

However in electrical engineering we always learn that the energy of a wave is the square of its magnitude; nothing to do with frequency.

So are these 2 concepts equivalent?

Thanks.

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Duplicate –  Vijay Murthy May 13 '12 at 9:33
The energy of a photon is $h\nu$, but that's the energy of an individual photon, not of the whole wave. The wave coming from, for example, your laser is made up from multiple photons and if you add up all the energies of the individual photons you'll get the total energy of the wave.