Section 1 Particles and Radiation

Question 1

What is the mass (in kg) of the nucleons?

Answer 1

1.67x10‐²⁷ kg

Question 2

What is the mass (in kg) of the Electron?

Answer 2

9.11x10‐³¹ kg

Question 3

What is the value (in Coulombs) of 1e - the relative charge?

Answer 3

±1.6x10‐¹⁹

Question 4

What is specific charge?

Answer 4

It’s the ratio of a particles charge to its mass, therefore charge÷mass

Question 5

What is an isotope?

Answer 5

An element with the same number of protons and electrons, but a different number of neutrons.

Question 6

What forces are acting on the nucleus?

Answer 6

Electromagnetic force between the protons causing them to repell.
Gravitational force holding the particles together (kind of)
The strong nuclear force

Question 7

What is the strong nuclear force?

Answer 7

An attractive force that holding the nucleons together

Question 8

What are the properties of the strong nuclear force?

Answer 8

Acts on a small range of a few femtometres
It is attractive to nucleons up to 3fm away
It is repulsive to nucleons closer than 0.5fm away so that the nucleus does not collapse

Question 9

What is an alpha particle?

Answer 9

Helium nucleus- 2 protons 2 neutrons

Question 10

How do the proton and nuleon number change druing alpha decay?

Answer 10

Proton number decreases by 2
Neucleon number decreases by 4

Question 11

Bigger atoms are more likely to experience _____ decay
Neutrons rich atoms are more likely to experience _____decay

Answer 11

Big- alpha
Neutrons rich- beta minus

Question 12

What is a beta particle?

Answer 12

A high energy electron

Question 13

What happens during beta minus decay?

Answer 13

A high energy Electron gets ejected by the nucleus, along with an Electron antineutrino which accounts for the loss of energy during beta decay
A neutron turns into a proton.

Question 14

How do the nucleon and proton number change during beta minus radiation?

Answer 14

Proton number increases by 1
Nucleon number stays the same

Question 15

Which scientist hypothesised the antineutrino?

Answer 15

Wolfgang Pauli

Question 16

What are photons?

Answer 16

‘Wave packets’ that are carriers of energy

Question 17

How do you figure out the energy of a photon?

Answer 17

E=hf=hc/wavelength

Question 18

What is pair production and how does it occur?

Answer 18

Pair production is the process of turning energy into mass, this happens when two particles collide with enough energy that they produce equal amounts of matter and antimatter
Photons- given they have enough energy- will also produce an Electron positron pair usually when it’s near a nucleus

Question 19

What is annihilation?

Answer 19

When a particle meets it’s antiparticle
The mass of both get converted back to energy un the form of 2 gamma ray protons

Question 20

What are Hadrons?

Answer 20

Particles affected by the strong force

Question 21

What are Baryons?

Answer 21

Non fundamental particles made from 3 quarks with a baryon number of +1
eg protons, neutrons, others like sigmas

Question 22

What are Mesons?

Answer 22

Particles made from a quark/anti quark pair with a Baryon number of 0.
eg pions, kaons, and other mesons.

Question 23

What is neutron decay?

Answer 23

When beta decay occurs, a neutron becomes a proton due to the WEAK INTEREACTION, when the nucleus is too neutron rich. A neutron turns into a proton, Electron and antineutrino.

Question 24

What are the 5 things that must be conserved during any interaction?

Answer 24

Energy
Momentum
Charge
Lepton number
Boson number

Question 25

What is Electron capture?

Answer 25

proton rich nuclei steal inner electrons using the weak intereaction

Question 26

What is the minimum energy required for pair production?

Answer 26

The minimum energy required for this is Emin=2E⁰

Question 27

What particles are affected by the strong force?

Answer 27

Hadrons only

Question 28

What is the gauge boson for the strong force?

Answer 28

Pions/Gluons

Question 29

What particles are affected by the electromagnetic force?

Answer 29

Charged particles only

Question 30

What are the gauge bosons for the electromagnetic force?

Answer 30

Photons

Question 31

What particles are affected by the weak force?

Answer 31

All types

Question 32

What is the gauge boson for the weak interaction?

Answer 32

W+ and W- bosons

Question 33

What is a use of isotopic data?

Answer 33

The use of measuring the % of Carbon 14 left in a fossil.
All living things have the same Carbon 12 and 14 ratio, Carbon 14 decays.
Can be used to date fossils

Question 34

What is the definition of an antiparticle?

Answer 34

A particle with the same mass, but opposite characteristics to a corresponding particle.

Question 35

What is the photoelectric effect?

Answer 35

The photoelectric effect is the emission of electrons from a material when it is exposed to light or electromagnetic radiation.

Question 36

Fill in the blank: The minimum frequency of light required to cause the photoelectric effect is called the __________.

Answer 36

threshold frequency

Question 37

In what type of interaction is strangeness conserved, why?

Answer 37

In the strong interaction, because only the weak interaction can change quark structure therefore change strangeness

Question 38

Strangeness can only change by __ in a weak interaction.

Answer 38

1

Question 39

What is the maximum kinetic energy of a photoelectron proportional to?

Answer 39

The frequency of the radiation