Quantum Mechanics

Question 1

What is exchanged in the electromagnetic force?

Answer 1

Virtual photons

Question 2

What does the strong force do?

Answer 2

Holds together neutrons and protons in a nucleus

Holds quarks together

Question 3

What does the weak force do?

Answer 3

It changes protons to neutrons OR neutrons to protons

Changes quark flavour

Question 4

What are the products of ß+ decay?

Answer 4

Positron + neutrino

Question 5

What are the products of ß- decay?

Answer 5

Electron + anti neutrino

Question 6

What exchange particles initiate the weak force?

Answer 6

W+/W- bosons

Z bosons

Question 7

What is a proton made from?

Answer 7

uud (quarks)

Question 8

What is a neutron made from?

Answer 8

udd (quarks)

Question 9

What is a baryon?

Answer 9

Something made of 3 quarks e.g. proton/neutron

Question 10

What is a meson?

Answer 10

Something made of 2 quarks e.g. kaons and pions

Question 11

What is a kaon?

Answer 11

Made of 2 quarks (one quark, one anti quark)

One of the quarks must be strange

Question 12

Order of mass of charged leptons (lightest to heaviest)

Answer 12

Electron
Muon
Tau

Question 13

What are hadrons?

Answer 13

Groups of quarks e.g. baryons and mesons

Question 14

When is strangeness conserved/ not conserved?

Answer 14

CONSERVED: strong/electromagnetic

NOT CONSERVED: weak interaction

Question 15

Charge of up, down and strange quarks:

Answer 15

Up: 2/3
Down: -1/3
Strange: -1/3

Question 16

What is produced during annihilation?

Answer 16

2 photons

Question 17

What is produced in pair production?

Answer 17

Particle + anti particle

Question 18

When does positron emission happen?

Answer 18

When a proton changes to a neutron in an unstable nucleus with too many protons (a neutrino is also emitted)

Question 19

Particle + corresponding anti particle ——> …

Answer 19

• -> total mass goes to photons
• -> have same rest mass
• -> equal/opposite charge

Question 20

When does pair production occur?

Answer 20

When a photon with sufficient energy passes a nucleus or an electron, they can suddenly turn into a particle/anti particle pair

Question 21

What is the definition of 1 eV?

Answer 21

1eV is the energy transferred when an electron is moved through a potential difference of 1V

Question 22

1 MeV = ?J

Answer 22

1 MeV = 1.6 x 10^-13 J

Question 23

Equation for Planck’s constant:

Answer 23

E=hf

E = mc^2 = hf

Question 24

1V = ?

Answer 24

1V = 1 J/C (joule per coulomb)

Question 25

Energy =

Answer 25

Momentum x Velocity

Question 26

How do muons, kaons and pions decay?

Answer 26

Muon - weak force Kaon - weak force Pion - strong force

Question 27

Which exchange particle mediates the strong force?

Answer 27

Gluons (also pions)

Question 28

What's the difference between gluons and W bosons?

Answer 28

Gluons = strong force & have greater range | W bosons = weak force

Question 29

Times by what to convert eV to joules?

Answer 29

1.6 x 10^-19

Question 30

Times by what to get MeV to eV?

Answer 30

x 10^6

Question 31

Value of Planck's constant

Answer 31

6.63 x 10^-34

Question 32

In which processes can a proton change to a neutron?

Answer 32

Electron capture ß+ decay

Question 33

What happens in electron capture?

Answer 33

Proton + electron -----> neutron + neutrino

Question 34

What happens when a neutron and a neutrino interact?

Answer 34

Neutron + neutrino ---> proton + ß-

Question 35

What happens when a proton and anti neutrino interact?

Answer 35

Proton + anti neutrino ----> n + ß+

Question 36

K°

Answer 36

d ś

Question 37

K+

Answer 37

u ś

Question 38

K-

Answer 38

ū s

Question 39

Anti K°

Answer 39

Anti d | S

Question 40

π+

Answer 40

u | Anti d

Question 41

π-

Answer 41

ū d

Question 42

π°

Answer 42

u ū | d anti d

Question 43

What can a kaon decay into?

Answer 43

Pion Muon + anti neutrino Anti muon + neutrino

Question 44

What can a pion decay into?

Answer 44

Gamma photon Muon + anti neutrino Anti muon + neutrino Neutrino + anti neutrino

Question 45

What can a muon decay into?

Answer 45

Electron neutrino + anti muon neutrino + positron Anti electron neutrino + muon neutrino + electron