Is a photon's momentum transverse?

[ConradDJ]

I understand that light propagates as a transverse wave -- does this mean that the momentum carried by a photon is perpendicular to its path?

Thanks for the help.

 

[Doc Al]

No. The momentum of a photon (and of an electromagnetic wave) is in the direction of motion.

(Don't think of the photon as wiggling transversely as it travels; keep the classical electromagnetic wave picture and the photon picture separate.)

 

[Bob S]

As Doc Al states, the momentum of a photon is only in the direction of motion. If the photon strikes an electron and produces a photo electron (photoelectric effect). The transverse momentum of the electron (relative to the incoming photon direction) has to be balanced by the transverse momentum of the recoiling atom or lattice.