3.2.1.4 Particle Interactions

Question 1

What are the four fundamental interactions?

Answer 1

The four fundamental interactions are:
Gravity
Electromagnetic Interaction
Strong Nuclear Interaction
Weak Nuclear Interaction

Question 2

What are forces caused by?

Answer 2

Forces are caused by exchange particles.

Question 3

Describe Gravity.

Answer 3

Weakest Force
Infinite Range of action.
Attractive Force
All matter is affected by it.

Question 4

Describe the Electromagnetic force.

Answer 4

Stronger than gravitational forces
Infinite range of action
Can be both attractive and repulsive
Acts on charged particles

Question 5

Describe the Weak Nuclear Force.

Answer 5

Weaker than EM forces, but stronger than gravity.
Range of action does not extend beyond the nucleus.
Responsible for Beta decay and fusion reactions in stars.

Question 6

Describe the Strong Nuclear force.

Answer 6

Strongest Force
Shortest Range

Two types:

THE nuclear strong force keeps quarks together.
The residual nuclear strong force keeps nucleons together.

Question 7

What is the exchange particles for the strong nuclear force?

Answer 7

Gluons and Pions

Question 8

What is the exchange particles for the weak nuclear force?

Answer 8

W+ and W- Bosons

Question 9

What is the exchange particles for gravity?

Answer 9

Graviton

Question 10

What is the exchange particles for the electromagnetic force?

Answer 10

Virtual photon

Question 11

What is the relationship between the mass of the exchange particle and the range of the force?

Answer 11

The larger the mass of the exchange particle, the shorter the range of the force.

Question 12

What is another name for an exchange particle?

Answer 12

Gauge Boson.

Question 13

Describe the Feynman Diagram for Electron-Electron Repulsion.

Answer 13

2 Electrons entering, 2 Electrons exiting.

Exchange particle is a photon.

Question 14

Describe the Feynman Diagram for Electron-Proton Attraction.

Answer 14

An electron and proton entering
An electron and proton exiting
Virtual photon as the exchange particle.

Question 15

What is the interaction equation for Beta-Minus decay.

Answer 15

A neutron turns into a proton, an electron and an anti-neutrino.

Question 16

Describe the Feynman Diagram for Beta-minus decay.

Answer 16

Neutron entering.
Proton exiting
Electron and antineutrino exiting
Exchange particle is W- particle.

Question 17

What is the interaction equation for Beta-plus decay?

Answer 17

A proton turns into a neutron, a position and a neutrino.

Question 18

Describe the Feynman Diagram for Beta-plus decay.

Answer 18

Proton entering
Neutron exiting
Positron and neutrino exiting
W+ boson is the exchange particle.

Question 19

What is the interaction equation for Electron Capture?

Answer 19

A proton and electron interact to produce a neutron and a neutrino.

Question 20

Describe the Feynman Diagram for electron capture.

Answer 20

Proton and electron entering.
Neutron and neutrino exiting.
Exchange particle is W+ particle
Direction of arrow is from the proton side to the electron side (left to right).

Question 21

What is the interaction equation for Electron - Proton collision?

Answer 21

A proton and electron interact to produce an electron a neutrino.

Question 22

Describe the Feynman Diagram for electron proton collision.

Answer 22

Proton and electron entering
Neutron and neutrino exiting
W- Boson is the exchange particle
Direction of arrow is from the electron side to the proton side (right to left).

Question 23

What is the interaction equation for neutrino - neutron collisions?

Answer 23

A neutron and a neutrino interact to produce a proton and an electron.

Question 24

Describe the Feynman Diagram for neutron -neutrino collisions.

Answer 24

Neutron and neutrino entering
Proton and electron exiting
W+ boson as the exchange particle
Direction or arrow from neutrino side to the neutron side (right to left)

Question 25

What is the interaction equation for antineutrino - proton collisions?

Answer 25

A proton interacts with an antineutrino to produce a neutron and a positron.

Question 26

Describe the Feynman Diagram for antineutrino - proton collisions.

Answer 26

Proton and antineutrino entering
neutron and positron exiting
w+ boson as the exchange particle
arrow direction is from the proton side to the antineutrino side (left to right).