1. and 2. Particles Definitions

Question 1

Define alpha decay

Answer 1

The process of an unstable nucleus emitting an alpha particle ( two protons and two neutrons) to become more stable.

Question 2

Define annihilation

Answer 2

The process of a particle and its antiparticle colliding and being converted into energy. The energy is released in two photons to conserve momentum.

Question 3

Define antiparticle

Answer 3

All particles have a corresponding antiparticle with the same mass but opposite charge and conservation numbers.

Question 4

Define Baryon number

Answer 4

A quantum number that is conserved in all particle interactions. Baryons have a baryon number of +1 and non-baryons have a baryon number of 0.

Question 5

Define baryon

Answer 5

A class of hadron, that is made up of three quarks. The proton is the only stable baryon.

Question 6

Define beta-minus decay

Answer 6

The process of a neutron inside a nucleus throning into a proton and emitting a beta-minus particle (an electron) and an antineutrino.

Question 7

Define beta-plus decay

Answer 7

The process of a proton inside a nucleus turning into a neutron and emitting a beta-plus particle (a positron) and a neutrino.

Question 8

Define electron diffraction

Answer 8

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.

Question 9

Define electron-volt (eV)

Answer 9

The work done to accelerate an electron through a potential difference of 1V. 1eV is equal to the charge of an electron (E=qv)

Question 10

Define energy levels

Answer 10

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

Question 11

Define excitation

Answer 11

The process of an electron taking in exactly the right quantity of energy to move to a higher energy level

Question 12

Define Gauge boson

Answer 12

The exchange particle that transmit the four fundamental interactions between particles.

Question 13

Define ground state

Answer 13

The most stable energy level that an electron can exist in

Question 14

Define hadrons

Answer 14

A class of subatomic particle that experiences the strong nuclear interaction

Question 15

Define ionisation

Answer 15

The process of an atom losing an orbital electron and becoming charged

Question 16

Define isotope

Answer 16

Same number of protons but different numbers of neutrons

Question 17

Define isotopic data

Answer 17

Data from isotopes that can be used for a purpose, such as carbon dating

Question 18

Define kaon

Answer 18

A type of meson that decays into pions

Question 19

Define lepton number

Answer 19

A quantum number that in conserved in all particle interactions. Both electron lepton numbers and muon lepton numbers must be conserved.

Question 20

Define lepton

Answer 20

A group of elementary subatomic particles, consisting of electrons, muons and neutrinos

Question 21

Define meson

Answer 21

A class of hadron that is made of a quark and antiquark pair

Question 22

Define muon

Answer 22

A type of lepton that decays into electrons

Question 23

Define neutrino

Answer 23

A subatomic particle whose existence was hypothesised to maintain the conservation of energy in beta decay.

Question 24

Define nucleon number (A)

Answer 24

The sum of the numbers of protons and neutrons in a given nucleus

Question 25

Define nucleon

Answer 25

A proton or neutron

Question 26

Define pair production

Answer 26

The process of sufficiently high-energy photon converting into a particle and its corresponding antiparticle. To conserve momentum, this usually occurs near a nucleus

Question 27

Define photon

Answer 27

A packet of energy

Question 28

Define pion

Answer 28

A type of meson and the exchange particle for the strong nuclear force

Question 29

Define positron

Answer 29

A positively charged particle that is the antiparticle of an electron

Question 30

Define proton number (Z)

Answer 30

The number of protons present in the nucleus of a given element

Question 31

Define stopping potential

Answer 31

The minimum potential difference required to stop the highest kinetic energy electrons from leaving the metal plate in the photoelectric effect.

Question 32

Define strange particles

Answer 32

Particles that are produced through the strong interaction but decay through the weak interaction

Question 33

Define strangeness

Answer 33

A quantum number that is conserved in string interactions but not in weak interactions. This reflects that strange particles are always produced in pairs.

Question 34

Define strong nuclear force

Answer 34

A force that acts between nucleons in a nucleus to keep it stable. It is attractive of up to 3fm and repulsive at separations less than 0.5fm.

Question 35

Define threshold frequency

Answer 35

The minimum frequency of photons required for photoelectrons to be emitted from the surface of a metal plate through the photoelectric effect. It is equal to the metal’s work function divided by Planck’s constant.

Question 36

Define work function

Answer 36

The minimum energy required to remove an electron from a metal’s surface