Particles and radiation

Question 1

How do you calculate specific charge

Answer 1

Charge/Mass

Question 2

What is an isotope

Answer 2

Atoms with the same number of protons but different number of neutrons

Question 3

What is the strong nuclear force?

Answer 3

The strong nuclear force is a force that keeps nuclei stable. IT only acts on nucleons and has an attractive force at up to 3fm but a repulsive force from 0.5fm

Question 4

What is an unstable nuclei?

Answer 4

An unstable nuclei has either too many protons or neutrons or both.

Question 5

What is alpha decay?

Answer 5

Occurs in large nuclei when there is too many protons and neutrons.
Decays 4 2 so 2 protons go and 4 nucleons in total go

Question 6

What is beta minus decay.

Answer 6

Occurs when there are too many neutrons.Protons increase by 1 and nucleons stay the same.

Question 7

What features do particles and antiparticles differ in?

Answer 7

They have the same mass and rest energy however opposite charge and quark composition

Question 8

What equation links energy of a photon and frequency of electromagnetic radiation?

Answer 8

E = hf

Question 9

What is annihilation?

Answer 9

Where a particle and its corresponding antiparticle collide. As a result their masses are transferred to energy. This energy is released as 2 photons moving in opposite directions.

Question 10

What is a photon?

Answer 10

A photon is a packet of electromagnetic radiation that have no mass but transfer energy.

Question 11

What is pair production?

Answer 11

Pair production is where a photon is converted into an equal amount of matter and antimatter. This can only occur when the photon has an energy greater than the rest energy of both the new particles that it creates. Any spare energy is transferred to kinetic of the new particles.

Question 12

What are the four fundamental forces?

Answer 12

Gravity, electromagnetic, weak and strong.

Question 13

What are exchange particles and what are their functions.

Answer 13

Exchange particles carry energy and momentum between particles.

Question 14

What is the characteristics of the strong force (exchange particle, range and what it acts on)

Answer 14

Gluon, 3fm, hadrons

Question 15

What is the characteristics of the weak force (exchange particle, range and what it acts on)

Answer 15

W boson(W+ or W-), 10^-18, all particles

Question 16

What is the characteristics of the electromagnetic force (exchange particle, range and what it acts on)

Answer 16

Virtual photon, Infinite, particles with mass

Question 17

What are the characteristics of the gravitational force (exchange particle, range and what it acts on)

Answer 17

Graviton, infinite, particles with mass

Question 18

Which 4 interactions are the weak nuclear force responsible for?

Answer 18

Electron capture, Electron proton collision, Beta plus decay, Beta minus decay.

Question 19

What does electron capture look like?

Answer 19

Proton, electron -> neutron, electro neutrino
Transfer particle W+ boson

Question 20

What does electron-proton collision look like?

Answer 20

Proton, electron -> neutron, electro neutrino
Transfer particle W- boson

Question 21

What does beta plus decay look like?

Answer 21

Proton -> neutron, positron, electro neutrino
Transfer particle W+ boson

Question 22

What does beta minus decay look like?

Answer 22

Neutron -> proton, electron, anti electro neutrino
Transfer particle W- boson

Question 23

What are the two main classifications of particles?

Answer 23

Hadrons or leptons,
Leptons are fundemental particles meaning that they cannot be broken down any further.They do not experience the strong force
Hadrons are formed of quarks, they can experience the strong force

Question 24

What are the 2 subclasses of hadrons?

Answer 24

Baryons and mesons,
Baryons are formed of 3 quarks
Mesons are formed of a quark antiquark pair

Question 25

What is the baryon number?

Answer 25

The baryon number of a particle shows if it is a baryon (1), anti-baryon (-1) or not a baryon at all (0). The baryon number is always conserved.

Question 26

What do all baryons decay into eventually?

Answer 26

A proton, a proton is the only stable baryon and therefor all baryons will eventually decay into a proton.

Question 27

What is the lepton number?

Answer 27

The lepton number of a particle shows if a particle is a lepton(1), an anti-lepton(-1) or neither (0). The lepton number is always conserved.

Question 28

What is a muon?

Answer 28

A muon is sometimes known as a heavy electron, muons decay into leptons.

Question 29

What are strange particles?

Answer 29

Strange particles are particles which are produced by the strong nuclear interaction but decay via the weak interaction. The only strange particles we know are kaons- which decay into pions through the weak interaction.

Question 30

What is strangeness?

Answer 30

Strangeness is a property of a particle, which shows that strange particles must be created in pairs. Strangeness must be conserved in strong interactions however in weak interactions strangeness can change by 1.

Question 31

What are the 3 types of quark that you need to know?

Answer 31

Up, down and strange

Question 32

Given all baryons decay into protons, a neutron will decay into a proton - how does this happen?

Answer 32

neutron -> proton, electron, anti electro neutrino

Question 33

What different properties always have to be conserved?

Answer 33

Energy and momentum Charge Baryon number Lepton number

Question 34

What is the photoelectric effect?

Answer 34

The photoelectric effect is where photoelectrons are emitted from the surface of a metal after light above a certain frequency is shone on it. The certain frequency for different types of metal is called the threshold frequency.

Question 35

How does the photoelectric effect work?

Answer 35

EM waves travel in discrete packets called photons, which have an energy that is directly proportional to frequency. Each electron can absorb a single photon If the light intensity is increased more photoelectrons are emitted per second.

Question 36

What is the work function?

Answer 36

The work function of a metal is the minimum energy required for electrons to be emitted from the surface of a metal.

Question 37

What is the stopping potential?

Answer 37

The stopping potential is the potential difference you would need to apply across the mental to stop the photoelectrons. Finding the stopping potential allows you to find the maximum kinetic energy of the released photoelectrons given Ekmax = e x Vs where e = charge of electrons Vs = stopping potential.

Question 38

What is excitation?

Answer 38

When electrons gain energy from colliding with free electrons they can jump up an energy level.

Question 39

What is ionisation?

Answer 39

When electrons gain enough energy from colliding with free electrons to remove themselves from the atom entirely.

Question 40

How are photons released in excitation?

Answer 40

After electrons become excited, they quickly return to to their original energy level. When they return to the ground state they release their energy in the form of a photon.

Question 41

what types of properties can light be said to have?

Answer 41

wave and particle