Photoelectric effect and energy levels

What is a photon?

Packets of energy (light) that acts like a particle

Important equations to use:

Energy of a photon: E = h x f or E = h x c / wavlength

h x f (or E) = work function + kinetic energy of electron

Threshold frequency: f = work function / h

What is the photoelectric effect?

When light is shined at a metal plate one photon from the light collides with one electron in the metal, giving it enough energy to be removed from the metal.

What does this prove?

That light acts like a particle, if light was a wave then electrons would be released with any frequency of light (eventually).

Disproves wave theory

What happens if you increase the intensity of the light source?

-Only increase the no. photons given out per second

-If the photon have energy below the work function, increasing the number will still not release any more electrons.

What happens if you increase the frequency?

-Electrons on shells closer to the nucleus have enough energy to be released from the atom , so no. electron released increases

-Electrons on the outermost shells have more kinetic energy and move faster.

What is the threshold frequency?

The minimum frequency that would release an electron from the surface of the metal.

What is the work function?

Amount of energy the electron requires to be completely removed (just to remove it)