Particles

Question 1

Specific charge

Answer 1

Charge/mass

Question 2

What type of particles does the strong nuclear force act on?

Answer 2

Hadrons

Question 3

How does the strong nuclear force keep the nucleus stable?

Answer 3

Counteracts electrostatic forces of repulsion between the protons in the nucleus. It only acts on nucleons.

Question 4

What is the range of the strong nuclear force?

Answer 4

It has a short range. It is repulsive below 0.5 fm, and attractive up to 3-4 fm.

Question 5

What is the exchange particle of the strong nuclear force?

Answer 5

Gluons and pions.

Question 6

What type of particles does the weak nuclear force act on?

Answer 6

All particles. It is responsible for decay interactions. and quarks change flavour during interactions.

Question 7

What is the exchange particle for the weak nuclear force?

Answer 7

W+ and W- bosons.

Question 8

Is strangeness conserved in the weak nuclear force?

Answer 8

Strangeness is not conserved.

Question 9

What is the range of the weak nuclear force?

Answer 9

It has a short range of 10^-18 m.

Question 10

What type of particles does the electromagnetic force act on?

Answer 10

Charged particles. It is responsible for the repulsion and attraction of charged particles.

Question 11

What is the exchange particle for the electromagnetic force?

Answer 11

Virtual photons.

Question 12

What is the range of the electromagnetic force?

Answer 12

It has an infinite range.

Question 13

What type of particles does the gravitational force act on?

Answer 13

All particles with mass.

Question 14

What is an exchange particle?

Answer 14

It is a force carrier - exchange particles carry energy and momentum between particles.

Question 15

What is an anti-particle?

Answer 15

Particles that have the same rest energy and mass as a given particle, but all other properties are opposite.

Question 16

Electron capture

Answer 16

p + e- = n + ve

W+ boson

Question 17

Electron-proton collision

Answer 17

p + e- = n + ve

W- boson

Question 18

Beta plus decay

Answer 18

p = n + e+ + ve

W+ boson

Question 19

Beta minus decay

Answer 19

n = p + e- + ve

W- boson

Question 20

What is annihilation?

Answer 20

A particle and an anti-particle collide, masses are converted into energy. Energy is released in the form of two photons.

Question 21

Application: PET scanner

Answer 21

A positron emitting isotope is used, positrons collide and annihilate with naturally occurring electrons in the body. This emits gamma photons that can be easily detected in order to image the inside of the body.

Question 22

What is pair production?

Answer 22

Photons are converted into mass: a particle and an anti-particle. This can only occur when the photon has an energy greater than the total rest energy of both particles. Excess energy is converted into kinetic energy of particles.

Question 23

What is the only stable hadron?

Answer 23

Protons. All baryons will eventually decay into a proton.

Question 24

Is strangeness conserved in the strong nuclear force?

Answer 24

Strangeness is conserved.

Question 25

What is always conserved in particle interactions?

Answer 25

Energy, momentum, charge, lepton number, baryons number.

Question 26

What is a muon?

Answer 26

A heavy electron. Decays into electrons.

Question 27

What is the quark composition of a proton?

Answer 27

uud

Question 28

What is the quark composition of a neutron?

Answer 28

udd

Question 29

What is the quark composition of baryons?

Answer 29

Three quarks or three anti-quarks.

Question 30

What is the quark composition of mesons?

Answer 30

A quark and an anti-quark.