What is the photoelectric effect?

The photoelectic effect is when photoelectrons are released from a metal that light is incident upon. The photoelectrons are only emitted when the photons of light are above a certain threshold frequency and energy (called the work function). The energy of the photoelectrons is equivalent to the gaps in electron energy levels of the atoms that compose the metal. Each photon above the work function produces exactly 1 photoelectron and any excess energy is given to the photoelectron in the form of kinetic energy. If the frequency of the light is below the threshold frequency then no photoelectrons are released. 

GR

Related Physics A Level answers

All answers ▸

Explain how resonance occurs for a driven oscillating system and describe the effect of damping on the resonant frequency.


An electron moving at 1000 m/s annihilates with a stationary positron. What is the frequency of the single photon produced?


What is the 'centre of gravity' of an object and how do I calculate it?


How do I approach this question? Our teacher never explained it in class!