Particles

Question 1

What is specific charge?

Answer 1

Charge/Mass

Charge per Unit mass

Question 2

What is a nucleon

Answer 2

particle that is constituent of a nucleus

Proton or neutron

Question 3

What is an isotope?

Answer 3

Variants of the same element with the same amount of protons but different masses and number of neutrons

Question 4

State a use of radioactive isotopes

Answer 4

Carbon Dating

Working out the proportion of carbon 14 within a material

Can be used as an age estimate

Question 5

What is a. strong nuclear force?

Answer 5

A Fundamental force that keeps the nucleus bonded and stable

by counteracting electrostatic force of repulsion between protons under 3fm of distance

Binding nuelons together

Stopping the implosion of the atom by acting as a repulsive force below 0.5 femto meters

Question 6

Describe the range of the strong force

Answer 6

Past 3 fm it is repulsive (very slightly)

Question 7

What makes a nucleus unstable

Answer 7

a nuclei with too many protons or neutrons or too much energy

Question 8

How do nuclei with too many nucleons decay?

Answer 8

Alpha decay (Mass No 4 Atomic No 2)

Question 9

How do nuclei with too many neutrons decay (3)

Answer 9

Beta minus decay

neutron decays into a proton via the weak interaction

Quark has changed from Udd—> UUd

Question 10

How was the existence of the neutrino hypothesised?

Answer 10

Net Energy of particles after beta decay had decreased after the reaction
Therefore a particle with neutral charge and negligible mass was hypothesised to carry away the excess energy

Question 11

What is meant by beta minus decay? (3)

Answer 11

When a neutral turns into a proton
The atom releases an electron and anti neutrino
Down quark changes to an upquark

Question 12

What is an anti particle

Answer 12

For each particle there is a anti particle

Same rest energy and mass

opposite in charge and other qualities

Question 13

What is the anti particle of a neutral pion

Answer 13

A neutral pion (itself)

Question 14

Describe what occurs when a particle and its anti particle meet?

Answer 14

Annihilation

When a particle and its antiparticle collide

Total Rest energy and kinetic energy is converted two 2 gamma photons

Emitted in opposite directions to conserve momentum

Question 15

What is pair production

Answer 15

when a gamma ray photon of enough energy is converted into a particle-antiparticle pair each with identical kinetic energy.

Question 16

Name the 4 fundamental forces

Answer 16

Gravitational
Electromagnetic
Weak Nuclear
Strong Nuclear

Question 17

What is the exchange particle for the electromagnetic force

Answer 17

Virtual photon

Question 18

What particles are effected by the strong nuclear force

Answer 18

Hadrons

Question 19

What is the exchange particle for the weak nuclear force

Answer 19

The W Boson

W+ or W-

Question 20

What does the electromagnetic force act on

Answer 20

Charged objects

Question 21

When does the weak interaction occur

Answer 21

When a quark changes character/flavour
eg. u——> d

Question 22

What properties must be conserved in all particle interactions (5)

Answer 22

Momentum
Energy
Brayon number
lepton number
Charge

Question 23

What property isn’t conserved in the weak interaction

Answer 23

Strangeness

Question 24

What is a hadron

Answer 24

Particles made of 2 or more quarks and are held together by the strong nuclear force

Question 25

What are the classes of hadrons

Answer 25

Baryons - 3 quarks
Mesons ( 1 quark and an anti quark)

Question 26

What is the exchange particle of the strong force

Answer 26

pion

Question 27

What is a significant about a proton

Answer 27

Only stable baryon
All baryons eventually decay into protons

Question 28

1) what does a muon decay into
2) what does an anti muon decay into

In what interaction?

Answer 28

1) electron and anti neutrino
2) Positron and neutrino

Weak

Question 29

What does a Negative, positive an neutral pions decay into?

What interaction?

Answer 29

1) muon + antineutrino
2) anti muon + neutrino
3) 2 Photons

Strong creation decay weak

Question 30

What does a neutral, negative and positive kaon decay into (3 types for negative and positive

What interaction

Answer 30

Neutral = 2 pions (either + & - or 2 neutral)

Negative = Muon + anti muon neutrino
Or negative pion + neutral pion
Or neutral pion + muon + anti muon neutrino

positive = Anti Muon + muon neutrino
Or positive pion + neutral pion
Or positive pion + positive pion + negative pion

Strong creation , weak decay

Question 31

What is the strangeness value for a strange quark

Answer 31

-1

Question 32

Strange particles are produced through the ______________ and decay through the ____________

Answer 32

1) strong

2) weak