Chapter 24: Particle Physics

Question 1

How does the alpha scattering experiment give evidence of a small, dense nucleus?

Answer 1

Few alpha particles did not bounce back
Positive charge is not evenly distributed in the atom
Dense positive charge

Question 2

What are the main features of an atom?

Answer 2

• Proton
• Neutron
• Electron

Question 3

How many times bigger is an atom than a nucleus

Answer 3

Approximately 100,000 times

Question 4

nucleon

Answer 4

a particle that makes up a nucleus, a proton or neutron

Question 5

Isotope

Answer 5

Atoms of an element with different number of neutrons

Question 6

Strong nuclear force

Answer 6

Force that holds the nucleus together
Must overcome the electrostatic force of repulsion between protons

Question 7

What is the range of the strong force

Answer 7

Repulsive up to 0.5fm
Attractive up to 3fm

Question 8

What has a higher density: atom or the nucleus?

Answer 8

Nucleus is more dense since atom has a lot of empty space

Question 9

Does every particle have an antiparticle

Answer 9

Yes

Question 10

Similarities and differences between particles and antiparticles

Answer 10

Similarity: Mass
Difference: charge

Question 11

What is the name of the antiparticle of an electron?

Answer 11

positron

Question 12

What is a hadron

Answer 12

A type of particle which is affected by the strong nuclear force

Question 13

What are hadrons made up of?

Answer 13

Made up of quarks

Question 14

What are the classifications of hadrons?

Answer 14

• Baryon
• Mesons

Question 15

What are two examples of baryons?

Answer 15

protons and neutrons

Question 16

What are the four fundamental forces?

Answer 16

• Strong nuclear
• Weak nuclear
• Electrostatic
• Gravity

Question 17

What are leptons?

Answer 17

Fundamental particles which are not subject to the strong nuclear force

Question 18

Examples of leptons

Answer 18

• Electron
• Muon
• Neutrino

Question 19

Three types of quarks

Answer 19

• up
• down
• strange
• corresponding antiparticles

Question 20

What are the quark composition of protons and neutrons

Answer 20

Proton (uud)
Neutron (udd)

Question 21

True and False: quarks can be found on their own, pairs or in triplets

Answer 21

False, quarks can never be found on their own

Question 22

Beta minus decay

Answer 22

When a neutron turns into a proton, the atom releases an electron and anti electron neutrino

Question 23

Which quark decays into beta minus decay?

Answer 23

A down quark turns into an up quark

Question 24

What quantities must be conserved during the decay of particles?

Answer 24

Charge, mass, baryon and lepton number