Particles

Question 1

What is the mass and charge of a proton?

Answer 1

Mass: 1.67(3) * 10^(-27) kg
Charge: + 1.6 * 10^(-19) C

Question 2

What is the mass and charge of a neutron?

Answer 2

Mass: 1.67(5) * 10^(-27) kg
Charge: 0

Question 3

What is the mass and charge of an electron?

Answer 3

Mass: 9.11 * 10^(-31) kg
Charge: - 1.6 * 10^(-19) C

Question 4

What is ionisation?

Answer 4

When an atom gains or loses electrons.

If it loses electrons, it becomes +ve.
If it gains electrons, it becomes -ve.

Question 5

What is the formula for specific charge?

Answer 5

Specific Charge = Charge / Mass

Question 6

What are the units for specific charge?

Answer 6

C kg^(-1)

Question 7

What is the charge of an atom?

Answer 7

0

Question 8

Which part of an atom has the largest magnitude of specific charge?

Answer 8

Electron

Electrons have the same magnitude of charge as protons, but less mass.

Question 9

What is an isotope?

Answer 9

Atoms with the same proton number, but a different number of neutrons.

Question 10

Which force holds the nucleus together?

Answer 10

Strong Nuclear Force

Question 11

How does the strength of the strong nuclear force vary with nucleon separation?

Answer 11

• Below 0.5fm, it is repulsive.
• Between 0.5 and 3fm, it is attractive.
• Above 3fm, it is zero/has no effect. R. Negligible

Question 12

What is 1eV in Joules?

Answer 12

1.6 * 10^(-19) J

Question 13

What are the three types of elementary particles?

Answer 13

Quarks, leptons and bosons.

Question 14

What are the three types of quarks (at A-Level)?

Answer 14

Up, down, strange.

Question 15

What are the three types of leptons (at A-level?

Answer 15

Electrons, muons, neutrinos (electron and muon neutrinos).

Question 16

What are hadrons?

Answer 16

• Particles made of quarks.
• Experience the strong interaction.
• Include baryons + mesons.

Question 17

What are leptons?

Answer 17

• Elementary particles.
• Do not experience the strong force.

Question 18

What are baryons?

Answer 18

Particles made of 3 quarks or 3 antiquarks.

Question 19

What is the only stable baryon?

Answer 19

Proton

Question 20

What is the quark composition of protons?

Answer 20

uud

Question 21

What is the quark composition of neutrons?

Answer 21

udd

Question 22

What is a Σ particle?

Answer 22

A baryon containing a strange quark.

Question 23

What are mesons?

Answer 23

Particles made of a quark-antiquark pair.

Question 24

What are kaons?

Answer 24

Mesons that contain a strange quark.

Question 25

What is an antiparticle?

Answer 25

A particle with the same mass as the standard particle, but with opposite charge (and baryon/lepton number where applicable).

Question 26

What are the three types of interaction?

Answer 26

Strong, weak and electromagnetic.

Question 27

Which particles does the strong interaction affect?

Answer 27

Hadrons

Question 28

Which particles does the weak interaction affect?

Answer 28

* Hadrons + leptons * Hadron decay

Question 29

Which particles does the electromagnetic interaction affect?

Answer 29

Charged particles

Question 30

What is the exchange particle for the strong interaction?

Answer 30

Pion/Gluon

Question 31

What is the exchange particle for the weak interaction?

Answer 31

W+ or W- Boson

Question 32

What is the exchange particle for the electromagnetic interaction?

Answer 32

**Virtual** Photon

Question 33

What must be conserved in strong interactions?

Answer 33

* Charge * Baryon Number * Lepton Number * Strangeness ## Footnote Mass and momentum must also be conserved.

Question 34

What must be conserved in the weak interaction?

Answer 34

* Charge * Baryon Number * Lepton Number ## Footnote Mass and momentum must also be conserved.

Question 35

What **doesn't** need to be conserved in the weak interaction?

Answer 35

Strangeness

Question 36

What are the three types of decay?

Answer 36

Alpha, beta and gamma.

Question 37

Which **nucleus** is an alpha particle the same as?

Answer 37

Helium nucleus

Question 38

What is the nucleon number and proton number of an alpha particle?

Answer 38

Nucleon Number: 4 Proton Number: 2

Question 39

What is a β- particle?

Answer 39

A high speed electron. ## Footnote β+ particles are high-speed positrons.

Question 40

What is the equation for β- decay?

Answer 40

Neutron → Proton + β- + Anti-electron neutrino

Question 41

Why was the neutrino hypothesised?

Answer 41

To account for missing energy in β decay.

Question 42

What is the strangeness of a strange quark?

Answer 42

-1 ## Footnote Antistrange quarks have a strangeness of +1.

Question 43

What is annihilation?

Answer 43

When a particle meets its antiparticle, their mass is converted into **two** photons.

Question 44

What is pair production?

Answer 44

When a photon has enough energy (the combined rest mass of the particles) to create a particle and its corresponding antiparticle.