Particles and Waves

Question 1

Right and left hand rules

Answer 1

Left hand rule is for electrons
right hand rule is for positive particles

Thumb - force
Index finger - field
Middle finger - flow of particles

Question 2

How do particle accelerators work

Answer 2

Electrons are ejected from the cathode an are accelerated due to the potential difference. After they pass the anode they continue at constant speeds and then repeat the process.

Question 3

Name all 6 types of quarks

Answer 3

Top and bottom quarks
strange and charm quarks
up and down quarks

Question 4

Combinations of quarks

Answer 4

A combination of quarks is known as a hadron.
A meson consists of two quarks.
A baryon consists of three quarks.
protons and neutrons are baryons.

Question 5

Charges on quarks

Answer 5

up quark - 2/3
down quark - -1/3
anti up quark - -2/3
anti down quark - 1/3

Question 6

Name all 6 types of leptons

Answer 6

Electron and electron neutrino
Tau and tau neutrino
Muon and muon neutrino

Question 7

What are the fundamental forces

Answer 7

Gluon - strong nuclear force
W and Z bosons - weak nuclear force
Photons - electromagnetic force
Gravity

Question 8

What is beta decay?

Answer 8

It is when a neutron decays into a proton and an electron.
The nucleus then recoils the electron away.
A ghost particle called the neutrino is there too.

Question 9

What is a neutrino?

Answer 9

It is a ghost particle said to carry away the excess energy that the electron doesn’t during beta decay.

Question 10

What is anti matter?

Answer 10

It is when an anti-particle has the same mass but opposite electric charge as their equivalent particles.

Question 11

What is alpha decay?

Answer 11

It is the emission of 2 neutrons and 2 protons from the nucleus in the form of a helium nucleus

Question 12

What is nuclear fusion?

Answer 12

When two elements combine to make a new element and release huge amounts of energy. They must be at very high speeds and temperature to fuse together.

Question 13

What is nuclear fission?

Answer 13

When a neutron enters a nucleus and splits into two smaller nuclei releasing massive amounts of energy and more neutrons which would then cause a chain reaction as they would enter more nuclei.

Question 14

What is irradiance

Answer 14

Irradiance is the power incident per unit area

I = P/A
I1 d1 squared = I2 d2 squared

Question 15

What is the photoelectric effect?

Answer 15

When intense light falls on to a negatively charged metal. If the energy transferred to the electrons is sufficient enough, they will leave the metal (photoemission).

Question 16

Equations of photoemission?

Answer 16

E = hf
Eo = hfo
Ek = hf - hfo

Question 17

What are coherent sources

Answer 17

It is when two sources of waves interfere and have the same frequency, wavelength, velocity and have a constant phase relationship.

Question 18

What is constructive interference

Answer 18

Its when two coherent sources interfere at a point where the path difference of the waves is a whole number. crest to crest or trough to trough.

Path difference = m lamda where m is (1,2,3,4 etc.)

Question 19

What is destructive interference?

Answer 19

Its when two coherent sources interfere at a point where the path difference of the waves is half a whole number. crest to trough or trough to crest.

Path difference = (m+1/2) lamda where m is (1,2,3,4 etc.)

Question 20

What is a free atom?

Answer 20

One that does not experience forces due to surrounding atoms

Question 21

Name 3 states / orbits that an electron can move between

Answer 21

Ground state - lowest, most stable
exited states - the levels in between
Ionisation level - zero potential energy and can escape the atom.

Question 22

Information about the energy levels

Answer 22

Each state has a specific energy associated with it and for an electron to move between the levels, it needs to absorb or emit energy in the form of photons of light. it needs the exact amount of energy to move levels.

Question 23

What is the critical angle?

Answer 23

The critical angle is the incident angle at which the light refracts at a 90 degree angle from the normal

Question 24

What is total internal refraction

Answer 24

When the angle in the medium is larger than the critical angle and no light is refracted.

Question 25

What happens when light enters a medium

Answer 25

The light separates into its component colours and produces a spectrum. This happens because each colour is refracted by different amounts. The refractive index for each colour is different.