Question

the bohr model of the atom explained why emission spectra are discrete. it could also be used to explain the photoelectric effect. which is a correct explanation of the photoelectric effect according to the model?
electrons are emitted with more speed when brighter light strikes them.
electrons need small amounts of energy to be released from an atom.
electrons move between levels only if they are hit by the right frequency of light.
electrons need specific amounts of energy to jump levels and be emitted.

Explanation:

In the Bohr model, electrons occupy discrete energy levels. For the photoelectric effect, electrons need a specific amount of energy (equal to the energy - difference between levels) to jump levels and be emitted. Brighter light only affects the number of photons, not the energy of individual electrons in the context of the Bohr - model explanation of the photoelectric effect. Also, it's not just small amounts of energy in a general sense, but specific quantized amounts. And electrons moving between levels due to the right frequency of light is more about absorption/emission of photons in general spectral phenomena, while the key for the photoelectric effect is the energy needed for electrons to be emitted.

Answer:

Electrons need specific amounts of energy to jump levels and be emitted.