Nuclear and particle physics

What is the nucleon number?

The total number of protons and neutrons.

What is a strong nuclear force?

The force that holds the nucleus together, it is an attractive force that overcomes the electrostatic force.

What is a hadron?

A non fundamental particle, made up of quarks that experiences the strong nuclear force.

What is a lepton?

A fundamental particle that doesn't feel the strong nuclear force (e.g. electron or neutrino).

What is a neutrino?

A fundamental particle that has almost zero mass or electric charge.

What is an antiparticle?

It is a corresponding particle as the normal one with the same mass but with the opposite charge.

How is a particle-antiparticle pair made?

From a single photon that gains enough energy to produce that much mass, it often happens near a nucleus to conserve momentum.

What is annihilation?

When a particle collides with an antiparticle, the mass of both particles becomes energy.

What is a quark?

A fundamental particle that makes up hadrons

What combination of quarks makes up a proton?

Up, up, down.

What combination of quarks makes a neutron?

Up, down, down.

In terms of quarks, what is beta minus decay?

A neutron is changed to a proton so a down quark becomes an up quark plus an electron plus an anti neutrino.

In terms of quarks, what is beta plus decay?

A proton is changed to a neutron so an up quark becomes a down quark plus a positron and a neutrino.

What are properties of beta plus radiation?

It gets annihilated by an electron so nothing happens.

When does alpha emission occur?

In nuclei of very heavy atoms (unstable due to heavy mass).

When does beta minus emission occur?

In neutron-rich isotopes.

When does gamma emission occur?

When a nucleus has excess energy, the nucleus gets excited then energy is lost by emitting a gamma ray.

What is the decay constant?

The measure of how quickly an isotope will decay.

What is a half life?

The average time it takes for the number of undecayed nuclei to halve.

What is a mass defect?

The difference between the mass of a nucleus and and the mass of its constituent parts.

What is binding energy?

The energy required to separate all of the nucleons in a nucleus.

What is fission?

The splitting of a nucleus into smaller parts.

What happens in a fission (atomic) bomb?

Uncontrolled chain reaction, as lots of energy gets released during each fission it causes an explosion.

What is fusion?

The combination of two nuclei.

What are the conditions for nuclear fusion?

Only occurs when there is enough energy to overcome the electrostatic repulsion and so the nuclei get close enough to fuse.

What is radioactive decay?

The process in which unstable nuclei lose energy by radiation.

What is activity?

The rate at which a source of unstable nuclei decays.

What is carbon dating?

The process of using the radioactive isotopes in carbon 14 to determine the age or date of an organic substance.