Matter and Radiation, Quarks and Leptons

Question 1

1eV is…

Answer 1

The work done in accelerating an electron across a potential difference of 1 Volt

Question 2

1eV=size and unit?

Answer 2

1.6x10^-19J

Question 3

What is pair production?

Answer 3

A photon with sufficient energy passing near a nucleus or an electron would then change into a particle-antiparticle pair

Question 4

Strong nuclear force is felt by…

Answer 4

Quarks

Question 5

Weak nuclear force is felt by…

Answer 5

Any particle

Question 6

EM force is felt by…

Answer 6

Any charged particle

Question 7

Gravitation force is felt by…

Answer 7

Any particle with mass

Question 8

The exchange particle for EM force is…

Answer 8

Virtual Photons

Question 9

The exchange particles for weak nuclear force is…

Answer 9

W- and W+ Bosons

Question 10

Bosons have…(3)

Answer 10

• Non-zero rest mass
• Very short range of 0.001 fm
• They are positively or negatively charged

Question 11

What is annihilation?

Answer 11

The process when a particle and an antiparticle meet, resulting in the conversion of their total mass into photons

Question 12

Gravitational Force

Answer 12

• Weakest
• Infinite range
• Attractive force
• Exchange particle is Gravitron

Question 13

EM Force

Answer 13

• Stronger than grav
• Infinite range and keeps atoms together
• Gives atoms chemical, mechanical and electrical
• Exchange particle is Photon

Question 14

Weak Nuclear Force

Answer 14

• Weaker than EM force, stronger than grav
• Range doesn’t have have further than nucleus
• Responsible for B- decay and fusion in stars
• Exchange particle is W-,W+,Z^0

Question 15

Strong Nuclear Force

Answer 15

• Strongest force
• Range is only between neighbouring nucleons
• Keeps nucleons together
• Exchange particle is Gluon

Question 16

What is electron capture?

Answer 16

A proton interacts with an inner shell electron through weak nuclear force. Proton turns into a neutron (n) and the electron turns into a neutrino by the exchange of a W+ Boson.

Question 17

Lepton Characteristics (4)

Answer 17

• Fundamental
• Lepton number -+1
• Baryon number 0
• Strangeness 0

Question 18

Lepton names(4) and corresponding Anti-particle(4)

Answer 18

• Electron (positron)
• Muon (antimuon)
• Electron neutrino (electron antineutrino)
• Muon neutrino (muon antineutrino)

Question 19

Hadron Characteristics(2)

Answer 19

• Not fundamental

- Consist of two families (Baryons and mesons)

Question 20

Baryon Characteristics(4)

Answer 20

• Contain 3 quarks
• Baryon number -+1
• Lepton number 0
• Strangeness 0

Question 21

Baryon names(2) and Corresponding antiparticle(2)

Answer 21

• Proton(Antiproton)

- Neutron(Antineutron)

Question 22

Proton quark composition

Answer 22

u, u , d

Question 23

Antiproton quark composition

Answer 23

Anti u, Anti u, Anti d

Question 24

Neutron quark composition

Answer 24

u, d, d

Question 25

Antineutron quark composition

Answer 25

Anti u, Anti d, Anti d

Question 26

Mesons Characteristics(5)

Answer 26

- One quark and anti quarks - Baryon number 0 - Lepton number 0 - Decay into photons and leptons - Consist of two families (Pions and kaons)

Question 27

Pion Characteristics(2)

Answer 27

- Quark anti-quark pair | - Strangeness 0

Question 28

π- quark composition

Answer 28

down, anti up

Question 29

π+ quark composition

Answer 29

up, anti-down

Question 30

π0 quark composition

Answer 30

- up, anti-up - down, anti-down - it can be any combination of a quark and corresponding anti-quark

Question 31

Kaon Characteristics(1)

Answer 31

-Strangeness +-1

Question 32

K- quark composition

Answer 32

strange, anti-up

Question 33

K+ quark composition

Answer 33

up, anti-strange

Question 34

K^0 quark compostion

Answer 34

- down, anti-strange | - strange, anti-down

Question 35

Conservation Laws(4) in interactions

Answer 35

- Relative charge is conserved - Baryon number is conserved - Strangeness is only conserved involving strong force - Strangeness is not always conserved involving weak nuclear force, it can be 0,or change by +-1