particle interactions

Question 1

What is an alpha particle made out of?

Answer 1

two protons
two neutrons

Question 2

State what happens during a beta plus decay.

Answer 2

• proton turns into neutron
• beta plus particle (positron) is emitted
• electron neutrino is emitted

Question 3

State what happens during a beta minus decay.

Answer 3

• neutron turns into proton
• beta minus particle is emitted
• electron antineutrino is emitted

Question 4

State what happens during a beta plus and beta minus decay in terms of quarks.

Answer 4

→ beta plus: up quark changes into down quark
→ beta minus: down quark changes into up quark

Question 5

State what happens during electron capture.

Answer 5

→ proton in the nucleus captures an inner shell electron
→ proton turns into neutron
→ electron neutrino is emitted

Question 6

State what happens during a gamma decay.

Answer 6

energy is released in the form of a gamma ray photon

Question 7

What force is responsible for electron capture, beta plus and beta minus decays?

Answer 7

weak force

Question 8

What are the similarities between beta plus and beta minus decays?

Answer 8

→ both emit an antiparticle
→ nucleon no. stays the same in both
→ both occur due to weak force

Question 9

What are the differences between beta plus and beta minus decays?

Answer 9

→ beta plus:
emits positron + neutron number increases
→ beta minus
emits an electron + neutron number decreases

Question 10

Discuss the differences between the photoelectric effect and beta minus decay.

Answer 10

photoelectric effect:
→ e- emitted due to electromagnetic force.
→ no. of protons within metal stays the same
→ orbital electron is emitted

beta minus decay:
→ e- emitted due to weak force
→ no. of protons within nucleus changes
→ e- emitted from nucleus of the atom

Question 11

Discuss the similarities & differences between gamma decay and electron de-excitation processes.

Answer 11

→ both emit high energy photons from an atom
→ e de-excitation is due transition of e- between energy levels of an atom
→ gamma decay is due to transition between energy levels of nucleus itself

Question 12

Which decay is the most strongly ionising?

Answer 12

alpha

Question 13

State what happens during muon decay.

Answer 13

muon decays into
→ electron
→ electron antineutrino
→ muon neutrino

Question 14

State what happens during antimuon decay.

Answer 14

antimuon decays into
→ positron
→ muon antineutrino
→ electron neutrino

Question 15

What is meant by particle decay?

Answer 15

when a particle changes into another particle usually to stabilise the atom

Question 16

Which force is responsible for strange particle production? How many?

Answer 16

strong force

in pairs

Question 17

What is produced when a negative pion and a proton interact?

Answer 17

→ neutral kaon
→ lambda baryon

Question 18

What is produced when a positive pion and a proton interact?

Answer 18

→ positive kaon
→ sigma baryon

Question 19

What can kaons decay into?

Answer 19

pions, muons or antimuons

Question 20

Which force is responsible for strange particle decay?

Answer 20

weak force

Question 21

Name four quantum numbers that are conserved in all particle interactions.

Answer 21

→ charge
→ baryon number
→ lepton number
→ strangeness

Question 22

During which interaction is strangeness not conserved?

Answer 22

strange particle decay

Question 23

What does the squiggly line in a particle interaction diagram represent?

Answer 23

exchange particle

Question 24

What do the vertical and horizontal axis in a particle interaction diagram represent?

Answer 24

x → space
y → time

Question 25

What does a particle collision diagram show?

Answer 25

→ two incoming particles → an exchange particle → outgoing particles

Question 26

State the difference between electron capture and a electron-proton collision.

Answer 26

electron capture → W+ boson electron-proton → W- boson

Question 27

What does a particle decay diagram show?

Answer 27

→ one incoming particle → an exchange particle → outgoing particles

Question 28

State what is meant by annihilation.

Answer 28

→ when a particle meets its antiparticle → and releases electromagnetic radiation → in the form of two high energy photons

Question 29

What is the relationship between mass of particles and the energy released by them during annihilation?

Answer 29

greater mass = greater energy released

Question 30

What is the equation for rest energy?

Answer 30

E = mc^2

Question 31

What is the minimum energy of each photon emitted after annihilation?

Answer 31

minimum energy of each photon = rest energy of each particle

Question 32

Explain how to find the minimum frequency of an emitted photon.

Answer 32

1) find rest energy of particle & antiparticle 2) convert to joules 3) use E=hf to find frequency

Question 33

State what is meant by pair production.

Answer 33

high energy photons create particle-antiparticle pairs

Question 34

Why is a pair produced during pair production?

Answer 34

to conserve momentum.

Question 35

State how to calculate the minimum energy required to produce a particle-antiparticle pair.

Answer 35

minimum energy required = rest energy x 2

Question 36

State how to calculate the kinetic energy of a particle produced during pair production.

Answer 36

→ left over energy divided by two → left over energy = photon energy - minimum required energy

Question 37

State what happens during electron-proton collision.

Answer 37

→ proton decays into neutron → electron decays into electron neutrino

Question 38

In strange particle decay (weak interactions), how can strangeness change?

Answer 38

→ by 0 (conserved) → increase by one → decrease by one

Question 39

State what happens during an electron-proton collision.

Answer 39

→ electron collides with a proton → neutron + electron neutrino emitted

Question 40

State the exchange particle for the strong nuclear force.

Answer 40

pion