Particles - A Level AQA Physics

Nucleon

A proton or a neutron in the nucleus

Nucleon number/mass number

The total number of protons and neutrons in an atom.

Proton number/atomic number

The total number of protons in an atom

Specific charge

The ratio of charge to unit mass of a particle

Antiparticle

Subatomic particle with the same rest mass as it’s matter counterpart but with the opposite charge.

Annihalation

The process in which a particle and it’s corresponding antiparticle meet and their total mass is converted into energy, typically in the form of 2 photons.

Pair production

The process in which a photon converts into a particle-antiparticle pair.

What is the minimum energy of the photon in pair production equal to?

The total rest mass of the particle-antiparticle pair.

Strong nuclear force

The force that holds the nucleus together by countering the electrostatic force of repulsion between the protons.

Range of strong nuclear force

• Attractive from 3-4fm down

• Repulsive below 0.5fm

Unstable nuclei

Nuclei with either too many protons, neutrons or both causing the SNF to not be able

Alpha decay equation (Z/A X →)

Z-2/A-4 Y + 2/4 He

Beta minus decay equation (1/0 n →)

1/1 p + 0/-1 β + ̅ν_e

Beta plus decay equation (A/Z X →)

A/Z-1 Y + 0/+1 + 0/+1 β + ν

Beta minus decay