Chapter 1

Question 1

Proton and neutron mass (kg)

Answer 1

1.67x10-27 kg

Question 2

Proton and Electron Charge (Coulomb)

Answer 2

+1.60x10-19 (proton)
-1.60x10-19 (electrons)

Question 3

Electron mass (kg)

Answer 3

9.11x10-31 kg

Question 4

Definition of an isotope?

Answer 4

Atoms with the same number of protons and different number of neutrons (also called nuclides)

Question 5

What is specific charge and what is its equation?

Answer 5

It is a characteristic property of a nucleus
Specific charge =Charge (c) / mass (kg)

Question 6

What does the strong nuclear force do?

Answer 6

It overcomes electrostatic repulsion and holds nucleons together

Question 7

Range of the strong nuclear force

Answer 7

Very short range (about 3-4 fm (femtometers, 10^-15) down to about 0.5 fm where it becomes repulsive to stop protons and neutrons contracting.

Question 8

Alpha decay

Answer 8

A A-4 `` 4
X –> y + He
Z Z-2 2

Question 9

Beta minus decay

Answer 9

A A 0
X –> y + B + antielectron neutrino
Z Z+1 -1

Question 10

Betus plus decay

Answer 10

A A 0
X –> y + B + electron neutrino
Z Z-1 +1

Question 11

Gamma decay

Answer 11

A A 0
X –> y + gamma
Z Z 0

Question 12

What is a photon?

Answer 12

The electromagnetic waves emitted when charges particles lose energy (discrete amount)

Question 13

How can charged particles lose energy? (2 ways)

Answer 13

Slowing down/ changing direction
Moving to a lower energy level

Question 14

Photon energy equation

Answer 14

E=hf
E=hC/ wavelength

Question 15

What is the planck constant (h)?

Answer 15

h= 6.63x10^-34 Js

Question 16

What speed does a wave travel at (C) ?

Answer 16

the speed of light, C= 3x10^8

Question 17

What is an antiparticle?

Answer 17

Has the same rest mass as its opposing particle but has the opposite charge.

Question 18

What happens when a particle and a antiparticle meet?

Answer 18

They annihilate each other, converting all mass to energy in the form of a pair of photons.

Question 19

What is the minimum photon dictated by?

Answer 19

It is dictated by the rest energies of the annihilating particles
– 2E = 2hf(min) (2 particles create two photons moving in opposite directions)

Question 20

What is annihilating used in?

Answer 20

It is used in P.E.T scanners where positron emitting tracers are injected into a person, when the positrons meet electrons they annihilate and the produced gamma photons can be detected outside the body.

Question 21

What is pair production?

Answer 21

When a single photon spontaneously produces a particle/antiparticle pair.
- Particle/anti conserves charge
- the opposite direction conserves momentum
- Min photon energy: hf(min)=2E (rest energy of each particle)

Question 22

What do we measure particle energy in?

Answer 22

electron volts
1eV = 1.6x10^-19 J

Question 23

What is 1MeV in J?

Answer 23

MeV = 1.6x10^-19 J

Question 24

What is the rest energy of an electron/positron?

Answer 24

0.551 MeV

Question 25

What exchange particle causes the strong nuclear force (like charges repelling)?

Answer 25

Virtual photon

Question 26

What force causes beta decay and what is the exchange particle?

Answer 26

Weak nuclear force W boson

Question 27

Difference between photons and W bosons

Answer 27

W bosons: have a rest mass have a very short range (~0.001fm) are charged

Question 28

Other weak nuclear force interactions

Answer 28

- Neutron interacting with a neutrino, changes into a proton and beta minus particle - Proton interacting with an antineutrino, changes into neutron and beta plus particle

Question 29

Electron capture mechanism

Answer 29

A proton interacting with an electron changing into a neutron and neutrino (W+ Boson)

Question 30

What does a force carrier do?

Answer 30

They are exchanged when the electromagnetic force and the weak nuclear force act.

Question 31

3 example of force carriers

Answer 31

Gamma photons W Bosons The pion

Question 32

What interaction is the pion responsible for?

Answer 32

The strong nuclear force.