# What exactly determines the energy of a wave? the intensity? or the frequency?

1. Feb 20, 2012

### mutineer123

I am taking AS level Physics rite now, and wanted to know what exactly determines the energy of a wave. Well since I have recently learn of stationary waves(sound waves) being standing. I know that they are formed by the superimposition of the reflected waves on the incident waves. This causes the amplitude to cancel out, and become zero. So intuitively I guess the frequency decides a waves energy, because if intensity did, then in a stationary wave, the amplitudes canceling out would make the intensity nil as well(I=ÎºA6^2), so this will make the sound stop, which it clearly does not.
So is this reasoning right?

2. Feb 20, 2012

### glenn21

It depends on the context actually. In terms of mechanical waves, for example a water wave ripple in a pond, more energy is carried by the wave for high amplitudes. Photons are another type of wave, but they carry energy in their frequency. A sound wave is a mechanical wave, and so the amplitude determines the energy of the wave.