Section 1: Particles And Radiation

Question 1

Mass of electron in Kg

Answer 1

9.11 x10^-31

Question 2

Charge of proton in Coulombs

Answer 2

+1.6 x10^-19

Question 3

Charge of neutron in Coulombs

Answer 3

0

Question 4

Charge of electron in Coulombs

Answer 4

-1.6 x10^-19

Question 5

Definition of specific charge

Answer 5

‘Charge per unit mass’

Question 6

Specific charge formula

Answer 6

Specific charge = charge
——–
Mass

Question 7

Relative strength of gravity

Answer 7

6 x10-39

Question 8

Relative strength of electromagnetic force

Answer 8

7 x10-3

Question 9

Relative strength of strong force

Answer 9

1

Question 10

Relative strength of weak force

Answer 10

1 x10-6

Question 11

i) Range of strong and weak force in metres

ii) What happens to the force beyond that range?

Answer 11

i) 10^-15m and 10^-18m respectively

ii) Completely drops off, doesn’t not gradually reduce

Question 12

Mass of proton or neutron in Kg

Answer 12

1.673 x10^-27

Question 13

What forms alpha decay?

Answer 13

2 neutrons and 2 protons

Question 14

When does alpha decay happen

Answer 14

When the diameter of the nucleus is greater than the range of the strong force

Question 15

How is energy conserved by alpha decay?

Answer 15

Always emitted at the same speed which means they have the same kinetic energy, therefore energy is conserved

Question 16

Name three quarks.

Answer 16

Up, down and strange

Question 17

What is the baryon number of a quark?

Answer 17

+1/3

Question 18

Give the quark composition of a:

a) proton
b) neutron
c) antineutron

Answer 18

a) uud
b) udd
c) udd (antiparticles)

Question 19

What is the quark composition of a meson?

Answer 19

1 quark and 1 antiquark

Question 20

Why can you not have quark on its own?

Answer 20

The energy used to remove a quark from a hadron creates a quark-antiquark pair. Quark confinement

Question 21

What kind of interaction can change a quark’s character? Name and describe an interaction in which this happens.

Answer 21

The weak interaction. In beta minus decay, a neutron decays into a proton so a down quark changes to an up quark

Question 22

What is the strangeness of a strange quark?

Answer 22

-1

Question 23

What is an exchange particle?

Answer 23

A virtual particle that lets a force act between two particles in an interaction

Question 24

Name two exchange particles of the weak interaction.

Answer 24

W+ boson and W- boson

Question 25

What do straight lines on particle interaction diagrams represent?

Answer 25

Particles (not exchange particles)

Question 26

Why would a nucleus undergo electron capture?

Answer 26

Because it is proton rich

Question 27

What is the difference between electron capture and electron-proton collisions?

Answer 27

In electron capture, a proton in a nucleus captures an electron from the atom, turning into a neutron and emitting a neutrino. In an electron-proton collision, a free electron collides with a free proton to produce a neutron and neutrino

Question 28

What are the exchange particles in the fundamental forces also known as?

Answer 28

Gauge bosons

Question 29

Which particles are affected by the strong force?

Answer 29

Hadrons

Question 30

The electromagnetic force affects...?

Answer 30

Charged particles

Question 31

Give the gauge boson for the electromagnetic force.

Answer 31

Virtual photon

Question 32

In what type of interaction are strange particles produced in pairs?

Answer 32

Strong interaction

Question 33

What special property do strange particles have?

Answer 33

Strange particles are always produced in pairs

Question 34

In what type of interaction do strange particles decay?

Answer 34

The weak interaction

Question 35

In what type of interaction is strangeness not conserved? By how much does the strangeness change in this reaction?

Answer 35

The weak interaction. Strangeness can differ in a range of 1 (-1, 0, +1)

Question 36

What is always conserved in particle intervention? (3)

Answer 36

Charge, baryon number, lepton number. (energy, mass and momentum are also conserved)

Question 37

What is a photon?

Answer 37

A packet of EM radiation

Question 38

What equation would you use to calculate the energy of a photon from its wavelength?

Answer 38

E =hc/wavelength

Question 39

How does an antiparticle differ from its corresponding particle?

Answer 39

Opposite charge

Question 40

Name the electron's antiparticle.

Answer 40

The positron

Question 41

Describe the process of pair production.

Answer 41

Energy can be converted into mass and produce particles, if there is enough energy. The mass is always produced in a particle-antiparticle pair.

Question 42

What is produced in the annihilation of matter and antimatter?

Answer 42

Two gamma ray photons

Question 43

What are the two largest forces acting on the particles in a nucleus?

Answer 43

The electromagnetic force (between protons) and the strong force

Question 44

What is the range of repulsion of the strong nuclear force?

Answer 44

Between 0 and 0.5fm

Question 45

What is the range of attraction of the strong nuclear force?

Answer 45

Between 0.5 and 3fm

Question 46

Why does a nucleus undergo nuclear decay?

Answer 46

Because the forces acting on the nucleus only have a range of a few femtometres so they struggle to keep the nuclei together making it unstable

Question 47

How do the nucleon and proton number change after alpha decay?

Answer 47

The nucleon number goes down by 4 and the proton number goes down by 2

Question 48

What particles are emitted during beta-minus decay?

Answer 48

An electron and an antineutrino

Question 49

Describe the changes in the nucleus of an atom when it undergoes beta-minus decay.

Answer 49

A neutron turns into a proton so the nucleon number stays the same and the proton number increases by 1