How would you explain the photoelectric effect in terms of energy?
A minimum amount of energy (called the work function ) is required to dislodge a photon from a surface. That energy must be delivered by a single packet of light energy, otherwise known as a photon.
Photons are "packets" or particles of light, each containing as specific amount of energy, which is the product of the frequency of the light.
The energy of a single photon is
What this means is if, for example, the work function of an electron on a surface is 2 eV (which is
We can calculate the minimum frequency of light required to dislodge the electron:
Light with a lower frequency will never dislodge that electron.
Light with a higher frequency can give the photon extra kinetic energy to fling it away from the surface faster.