Consider figure for photoemission. How would you reconcile with momentum-conservation? Note light (photons) have momentum in a different direction than the emitted electrons

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Solution

When an electromagnetic wave strikes the surface of a metal, at microscopic level, atoms of a metal absorb the photon and its momentum is transferred mainly to the nucleus and electrons.

The excited electrons emit approximately opposite to the direction of photons.

Conservation of momentum needs to be accounted for the momentum transferred to the nucleus and electrons.

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