Physics P1 - Photoelectric Effect

What is the photoelectric effect?

Where photoelectrons are emitted from the surface of a metal after light above a certain frequency is shone on it.

What is the threshold frequency?

The minimum frequency of light required for an electron to be emitted.

What is the photoelectric effect?

Where photoelectrons are emitted from the surface of a metal after light above a certain frequency is shone on it.

What is the threshold frequency?

The minimum frequency of light required for an electron to be emitted.

Why can't the threshold frequency be explained by the wave theory?

It suggests that any frequency of light should be able to cause photoelectric emission as the energy absorbed by each electron will gradually increase with each incoming wavefront.

Why can the photon model explain the photoelectric effect?

Each electron absorbs a single photon, therefore a photoelectron can be emitted only if the frequency is above the threshold.

What happens when the intensity of the light is increased?

As long as the frequency is above the threshold, if the intensity increases, more photoelectrons are emitted.

What is the work function?

The minimum energy needed by an electron to escape the metal surface.

What is the stopping potential?

The potential difference you would need to apply across the metal to stop the photoelectrons with the maximum kinetic energy.

What does measuring stopping potential allow you to do?

Find the maximum kinetic energy of the released photoelectrons.

What equation links stopping potential and kinetic energy?

Maximum kinetic energy = charge of electron * stopping potential

What is Einstein's photoelectric equation?

E = hf

What equation links frequency and the work function?

hf = work function + maximum kinetic energy