Quantum Physics Definitions

Ground state

The lowest and most stable energy level an atom or electron can occupy.

Specific Charge

Charge per unit mass.

Stopping Potential

The minimum potential difference required to stop the electrons with the highest kinetic energy leaving the metal plate.

Work Function

Minimum energy required for an electron to escape the surface of a metal.

Electron Volt

The energy gained by an electron when it passes through a potential difference of 1V.

Threshold Frequency

Minimum frequency the photon needs in order for a photoelectron to be emitted from the surface of a metal through the photoelectric effect.

Photoelectric Effect

When electromagnetic radiation is incident on a metal surface and one electron gains sufficient energy from one photon to escape the surface of the metal.

Intensity

Energy transferred per unit time per unit area.

Ionisation Energy

The minimum energy required to remove an electron from ground state from the atom.

Excitation Energy

The energy required to move an electron from ground state to a higher energy level.

Quantisation of Energy Levels

Electrons are only able to occupy energy values of specific or discrete quantities. This means to move from one energy level to another they need to absorb a specific amount of energy,

Electron diffraction

The spreading of electrons as they pass through a gap similar to the magnitude of their de Broglie wavelength. It is evidence of the wave-like properties of particles.

Energy levels

Defined and distinct energies at which electrons can exist in an atom. An electron cannot exist between energy levels.

Ionisation

The process of an atom losing an orbiting electron and becoming charged.

Photon

A packet of electro magnetic energy