What color of light has the most energy?

Violet.

Violet waves have the most of the visible spectrum.

Remember: ##" "c=flambda##

Therefore: ##" "f=c/lambda##

Here ##c## is the speed of light in a vacuum.

So:

As wavelength decreases, frequency increases and, as ##E=hf##, where ##h## is constant (Planck's constant), so does the energy that the waves carry. Waves with a short wavelength have the most energy.

Red waves have a relatively long wavelength (in the 700 nm range), and violet waves are much shorter - roughly half that.

Because violet waves have the shortest wavelength of the visible light spectrum, they carry the most energy.