particle physics Flashcards

You may prefer our related Brainscape-certified flashcards:
1
Q

beta minus decay

A

n protons increase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

when describing decay process (3)

A
  • name decay
  • how does nucleon n change
  • how does atomic number change
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

(2) why alpha radiation not pose any risk in the smoke detector

A

(1) only small quantity needed (highly ionising and long half-life
(1) particles do not travel more than a few cm’s (penetrating ability)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

what is ionisation ?

A

Ionisation is the removal (or addition) of electrons from (to) an atom or molecule

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

why leptons cannot decay further

A

stable (fundamental)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

explain why when UV shone on positiviley charged plate no charge is lost

A

process involved the ejection of electrons(1)

which only make it more positive(1)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

2 differences exchange particle weak + strong

A

gluons lighter bosons more massive (1)

gluons have longer range bosons have shorter range (1)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

explain what is meant by an exchange particle (2)

A

moves between one object and another/carrier acting
on two particles
gives rise to the force between the particles

     gluon(s) (accept pions
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

The deuterium nucleus is stable.
Describe how the variation of the strong nuclear force with distance contributes to the
stability of the deuterium nucleus.
[3 marks]

A

(Short-range) attraction up to about 3 fm  (Very short-range) repulsion closer than 0.5 fm 
Prevent proton and neutron moving closer or further apart 

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

exchange particle of strong nuclear force

A

pion/gluon

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Tritium is an isotope of hydrogen. Its nucleus contains one proton and two neutrons. Tritium undergoes radioactive decay.
Three modes of radioactive decay are
• alpha decay −
• beta minus (β ) decay • electron capture.
Deduce which of these modes could produce the nucleus of another element when
the tritium nucleus decays.
[3 marks]

A
Correct description of alpha decay
OR
Consequence of alpha decay
Correct description of electron capture
OR
Consequence of electron capture
Correct description of beta decay, with explicit conclusion that this mode is valid
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

whats released in annihilation

A

photon(s) of !electromagnetic radiation!

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

why mass is not always conserved

A

mass can be converted to energy and vice versa

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

In the strong interaction,
K– + p → K0 + K+ + X,
deduce the quark composition of, and state the type of, hadron represented by X.

A

X = sss (1) (= Ω–)

baryon (1)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

A positive muon may decay to a positron and two neutrinos. Write down an equation representing the muon decay.
μ+ →

A

μ+ → e+ + ve + (+Q)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

instead of saying escape metal say

A

overcome work function

17
Q

what is meant by threshold frequency

A
  • below a certain frequency no electrons emitted

- minimum frequency for electrons to overcome work function

18
Q

why the photoelectric effect is not observed below a certain frequency? (3)

A
  • energy photon depends on the frequency (1)
  • below threshold frequency photon does not have enough energy to liberate electron (1)
  • photon does not have enough energy to overcome work function
19
Q

what’s threshold freq?

A

minimum energy required for electron to escape surface of metal

20
Q

ionisation energy

A

energy to remove electron from ground state

21
Q

explain process pair production (3)

A

photon interacts w/ orbital electron
energy photon creates particle anti particle pair
to conserve momentum photon interacts w/ intracting particle

22
Q

calculate max frequency photons in annihilation 2 points

A

freq of one photon

mark scheme says must show explaining how it’s two

23
Q

role exchange particles in exchange forces between particles (1)

A

forces arise when exchange particles move between other particles

24
Q

a discussion of the stability of free hadrons

- what is most stable baryon

A

proton

25
Q

a discussion of the stability of free hadrons.]

mesons

A
  • kaon decay into pions
26
Q

is X and Y same charge but X greater mass determine nuclear compositions diff

A

same number protons but X has more neutrons

27
Q

when would weak nuclear force be responsible for something

A
  • change in quark type

- involved leptons AND hadrons

28
Q

weak nuclear force changes quarks by

A

By emitting an electrically charged W boson, the weak force changes the flavor of a quark, which causes a proton to change into a neutron, or vice versa.

29
Q

if leptons involved

A

can’t be strong nuclear force

30
Q

3 marker on how you can find interaction from resulting nucleus

A

go through equation and what is released / found

31
Q

why is it important for many diff ppl to take part in advances in particle physics

A

peer review
expensive (e.g. particle accelerator)
-many skills + disciplines needed

32
Q

for antiparticle definition

A

all properties opposite but mass number same

33
Q

don’t say mass say

A

rest mass

34
Q

baryon number of anti proton is

A

-1

35
Q

photon anti particle

A

it’s its own anti particle

36
Q

4 marker on how force works use EM and photon

A
  • EM
  • photon
  • trasnfer energy/momentum
  • particle receives exchange particle new particle creation occurs
37
Q

Ko made out of what

A

down anti strange

38
Q

on anti particle of electron say

A

positron (DO NOT ACCEPT ANTI ELECTRON)