Is the energy of a photon of light of wavelength λ, the smallest transferable energy unit for that same light?And is this the reason there is no partial transfer of energy in photoelectric effect, because then there will be quantisation of energy transfer during the photoelectric effect?

I’m new to the concept of photoelectric effect, so my question may sound ridiculous.


1 Answer 1


Yes, in a sense that full photon energy must be transferred for a photoelectric light absorption by ordinary matter (atoms). This is because there is a selection rule in electron orbital transitions, that only +/- 1 unit of angular momentum can be involved when a photon promotes an electron; if there are only two-particle interactions probable, then the photon must transfer all its angular momentum to cause the transition, and that must decrement the photon count... because photons are Bosons, have 1 unit of angular momentum.

The alternative, with a photon losing only some energy, would have to be a multiparticle event (two photons, two electrons) and those are very rare (in common parlance, forbidden) transactions.

There are partial-energy interactions, such as Doppler effect reflection from a moving mirror, which do happen, but those aren't photoelectric in nature.


Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.