Quantum Phenomena (Chapter 3)

Photoelectric Effect

When electrons are emitted from the surface of a metal due to an EM wave of frequency Fmin.

1:1 Interaction

Photons and electrons can only interact in a 1:1 ratio, if photons of insufficient energy are directed to a metal plate no photo electrons will be emitted.

Light Intensity Proportionality

The rate of the photoelectric effect is proportional to the intensity of the light shone on it.

Work Function

The minimum energy required by an electron to escape a metal’s surface.

Stopping Potential

The minimum potential needed to stop photoelectric emission, by attracting them back to a plate with sufficient positive charge.

Excitation

When an electron is moved to an outer shell either via absorption of a photon or collision with another electron.

Ionisation

When an electron is removed from an atom either via absorption of a photon or collision with another electron, causing the atom to lose an electron thus giving it an overall positive charge.

De-Excitation

When an electron moves from an outer to an inner shell, emitting a photon of energy equal to that lost in the movement between shells.

Energy Levels

Energy levels show the amount of energy either below the point of ionisation or above the standard amount that various levels of excitement occur at.

Diffraction

Where a wave spreads out as it travels.

Wave-Particle Duality

Particles such as electrons have characteristics of both waves and particles, as they are able to both diffract and also interact in a 1:1 ratio.