Particles and Waves

Question 1

Fermion:

Answer 1

Fundamental Particles that make up matter e.g. quark and leptons.

Question 2

Boson:

Answer 2

Force mediating particles.

Question 3

Hadrons:

Answer 3

Non fundamental massive particles.

Question 4

Meson:

Answer 4

A hadron made from a quark anti-quark pair.

Question 5

Bayron:

Answer 5

A hadron made from a 3 quarks.

Question 6

Antimatter:

Answer 6

Annihilates with matter to release energy. Has the same mass but opposite charge to matter.

Question 7

Quark:

Answer 7

Lepton with non integer charge e.g. up and down.

Question 8

Lepton:

Answer 8

Lepton with integer charge e.g. electrons.

Question 9

Irradiance definition:

Answer 9

The power per unit area incident on a surface.

Question 10

Inverse Square Law definition:

Answer 10

Irradiance is inversely proportional to the square of the distance from a point source. as distance increases by a factor of 2, irradiance decreases by a factor of 4.

Question 11

Absolute Refractive Index (n):

Answer 11

Tells us how refractive a material is, the greater the n, the smaller the angle of refraction in the material, the greater is the reduction in speed and wavelength.

Question 12

n definition:

Answer 12

The absolute refractive index of a material is the ratio speed of light in a vacuum to the speed of light in the material.

Question 13

Critical Angle definition:

Answer 13

Critical angle as the angle of incidence which produces an angle of refraction of
90°.

Question 14

Coherent Source definition:

Answer 14

A coherent source has a constant phase relationship. This means they will have the same frequency, wavelength, speed and be generated in phase.

Question 15

Interference definition:

Answer 15

Interference can occur when the waves from 2 or more coherent sources meet.

Question 16

Constructive Interference definition:

Answer 16

This will occur when the waves meet in phase, this will cause the amplitude to increase.

Question 17

Destructive Interference definition:

Answer 17

This will occur when the waves meet out of phase, this will cause the amplitude to decrease.

Question 18

Maxima definition:

Answer 18

Maxima are produced when the path difference between waves is a whole number of wavelengths. Crest meets crest, constructive interference causes the amplitude to double to the sum of the two coherent sources at that point.

Question 19

Minima definition:

Answer 19

Minima are produced when the path difference between waves is an odd number of half-wavelengths. Crest meets trough The point where destructive interference causes the amplitude to be 0, the sum of the two coherent sources at that point.

Question 20

Path Difference definition:

Answer 20

The difference in the path travelled by each wave until the point of interference. This can be calculated by subtracting the length travelled by wave 2 from wave 1.

Question 21

Diffraction Grating definition:

Answer 21

A material that has serval gaps and blocks in a short space. They are used to demonstrate interference of light. They typically have 100s of lines in every mm.

Question 22

Spectra definition:

Answer 22

Visible light split up into its component frequencies, can be absorption, continuous, emission or line emission.

Question 23

Energy Levels definition:

Answer 23

Electrons in an atom can be at discreet energy levels. They cannot exist in the spaces between these energy levels. Electrons can move between the levels by gaining or emitting energy.

Question 24

Ionisation Energy definition:

Answer 24

The Ei, is the energy required to remove an electron from an atom in its ground state to a free state in which it has no Ek i.e. its total energy is zero.

Question 25

Excitation Energy definition:

Answer 25

The energy required to promote an electron from one energy level to a higher energy state.

Question 26

Ground State definition:

Answer 26

The ground state is the lowest energy level where an electron can be found.

Question 27

Ionisation definition:

Answer 27

Process in which an electron is given enough energy to break away from an atom when the electron is just ionised it has zero potential energy.

Question 28

Fraunhofer Lines definition:

Answer 28

The lines missing when looking at the emission spectrum from the sun. this is because gases in the atmosphere of the sun absorb certain frequencies of light.

Question 29

Threshold Frequency definition:

Answer 29

The minimum frequency required to eject electrons is called the threshold frequency (fo).

Question 30

Work Function definition:

Answer 30

Work function is the minimum energy required to remove an electron from the metal. One photon will eject one electron.

Question 31

Forces according to the Standard Model:

Answer 31

Forces arise when a fermion produces a boson, which is then taken in by another fermion.

Question 32

Fundamental Forces in order of strength:

Answer 32

Strong Nuclear- gluon
Electromagnetic- photon
Weak- W and Z bosons
Gravitational- graviton

Question 33

Fundamental Particles definition:

Answer 33

Particles which cannot be broken down into smaller particles.

Question 34

Beta decay is evidence for:

Answer 34

Evidence of the neutrino.