What is the wavelength of a photon whose energy is twice that of a photon with a 622 nm wavelength?

The frequency of the  wavelength photon is given by

where c is the speed of light.

The energy of this photon is

where h is the Planck constant.

The energy of the first photon is twice that of the second photon, so


And so now by using again the relationship betwen energy and frequency, we can find the frequency of the first photon:


and its wavelength is

So, we see that the wavelength of the first photon is exactly half of the wavelength of the second photon (622 nm).

Tons?