Question

In which of the following situations is the photoelectric effect being demonstrated?
A. A photon of light travels at the speed of light in a vacuum but moves slightly slower through a medium made of matter.

B. An electron within an atom absorbs energy when it is hit by a photon and jumps to a higher energy level within the atom.

C. An electron moves through a sea of electrons within a block of aluminum atoms when a voltage is applied to the metal.

D. The color of a substance is determined by the wavelength of electromagnetic radiation that is reflected off of its surface.

Answer 1

Remarkably enough, none of these. The photoelectric effect is demonstrated when a photon hits a bonding (valence band) electron in a metal, and gives it enough energy to be ejected from the surface of the metal, or at least excited into the conduction band and produce an electric current in the metal.

The only scenario above that even comes close is the quantum transition of an electron in an atom from one bound state to another, after absorbing a photon. Since the electron isn't ejected from the atom -- no actual electric current is produced -- this isn't a photoelectric effect, but since the underlying mechanisms are at least similar, if you must choose one of these answers, I'd go with that one.

Answer 2

might be in B

Answer 3

only possible ans is B