J.R. S. answered 10/16/19
Ph.D. University Professor with 10+ years Tutoring Experience
White light is a mixture of photons, and these different photons have different energies. The greater the energy of the photon, the more it will be deflected by the prism. When you ask to describe white light in terms of a mixture of photons, that's exactly what it is. The only additional description would be to add that what is meant by "different photon" is photons of different energies.