Physics Revision Flashcards
1
Q
What is annihilation?
A
When a particle and an antiparticle meet, their mass is converted into radiation energy, producing two photons.
2
Q
What is pair production?
A
This is when a photon creates a particle and a corresponding antiparticle and vanishes in the process.
3
Q
What is the strong nuclear force?
A
It is the force that keeps the nucleus stable.
4
Q
What is the range of the strong nuclear force?
A
It has a short-range attraction up to 3fm and a very short repulsion closer than 0.5fm.
5
Q
What are the four fundamental interactions?
A
Gravity, electromagnetic, weak nuclear, strong nuclear.
6
Q
What are the exchange particles for weak nuclear interactions?
A
W bosons.
7
Q
What are the exchange particles for electromagnetic interactions?
A
Virtual photons.
8
Q
How do leptons interact?
A
Through weak, gravitational, and electromagnetic interactions (if charged).
9
Q
How do hadrons interact?
A
Through all four fundamental interactions.
10
Q
What are baryons?
A
Protons and all other hadrons that decay into protons either directly or indirectly.
11
Q
What are mesons?
A
Hadrons that do not include protons in their decay products (e.g., kaons, pions).
12
Q
What is the exchange particle of strong interaction?
A
Pion.
13
Q
What is a kaon?
A
A particle that can decay into pions.
14
Q
What does a muon decay into?
A
An electron.
15
Q
How are strange particles created?
A
They are produced through the strong interaction and decay through the weak interaction.
16
Q
What is the conservation of strangeness?
A
Strange particles are always created in pairs during strong interactions.
17
Q
What does a neutron decay into?
A
A proton, releasing an electron and an anti-electron neutrino.
18
Q
What is the pion + composition?
A
Up anti-down.
19
Q
What is the kaon + composition?
A
Up anti-strange.
20
Q
What is threshold frequency?
A
The minimum frequency required for electrons to be emitted from a metal surface.
21
Q
What is the work function?
A
The minimum energy needed by an electron to escape from the metal surface. Excess energy turns into kinetic energy.
22
Q
What is stopping potential?
A
The minimum potential needed to stop photoelectric emission.
23
Q
What is excitation?
A
The energy required to move an electron up an energy level.
24
Q
What is ionisation?
A
The minimum energy required to remove an electron from the ground state to escape.
25
What is a fluorescent tube?
A glass tube with a fluorescent coating on the inner surface that contains mercury vapour at low pressure.
26
When is the wave-like nature of light observed?
When diffraction of light takes place.
27
When is the particle-like nature of light observed?
In the photoelectric effect.
28
What are coherent sources?
Sources that emit light waves of constant phase difference and the same frequency.
29
What happens when a bright fringe is formed?
The light path from one slit reinforces the light waves arriving in phase with each other.
30
What happens when a dark fringe is formed?
The light waves from the two slits arrive 180° out of phase.
31
When does total internal reflection occur?
When the angle of incidence is greater than the critical angle.
32
When does modal dispersion occur?
When the optical path length varies with each mode.
33
When does material dispersion occur?
Due to the difference in speed between the colours of white light merging.
34
What is a couple?
A pair of equal and opposite coplanar forces.
35
What does the area under a force-time graph represent?
Impulse or change in momentum.
36
What is an elastic collision?
A collision in which the kinetic energy before the collision equals the kinetic energy after the collision.
37
What happens in an inelastic collision?
Momentum is conserved but kinetic energy is not.
38
What is the efficiency equation?
Useful energy output / total energy input.
39
What does the area under a force-displacement graph represent?
Total work done.
40
What does Ohm's Law state?
The potential difference across a metallic conductor is proportional to the current through it.
41
What is a superconductor?
A wire or device made of material that has zero resistivity at and below a critical temperature.
42
What are the uses of superconductors?
Used to make high power electromagnets that generate very strong magnetic fields and reduce energy loss in transmission of electrical power.
43
What is a potential divider used for?
To supply constant or variable potential difference from a power supply.
44
What is uncertainty?
+- half the range.
45
What is percentage uncertainty?
Uncertainty/mean x 100.
46
What does Lenz's law state?
The direction of the induced current is such to oppose the change that causes it.
47
What does Faraday's law state?
The induced emf in a circuit is equal to the rate of change of flux linkage through the circuit.
48
What is electric current?
The rate of flow of charge.
49
What is potential difference?
The work done per unit charge.
50
What is internal energy?
The sum of the randomly distributed kinetic energies and potential energies of the particles in a body.
51
What is the ideal gas equation?
PV=nRT (n moles).
52
What is Brownian motion?
Random movement of particles.
53
What are the assumptions of kinetic theory?
1. Molecules have negligible volume compared to the volume of gas. 2. The molecules do not attract each other. 3. The molecules move in continuous random motion. 4. The molecules undergo elastic collisions with each other and the container. 5. Each collision with the container is negligible compared to the time between collisions.
54
What is the definition of a Tesla?
When a wire carrying a current of 1 A is placed at right angles to the magnetic field, it experiences a force of 1 N per metre of its length.
55
What is resonance?
The system vibrates such that its velocity is in phase with the periodic force.
56
How does damping affect resonance?
The lighter the damping, the sharper the resonance curve.
57
What is the First Law of Thermodynamics?
The change in thermal energy of the object equals the total energy transfer due to work done or heating.
58
What are equipotentials?
Surfaces of constant potential where no work needs to be done across an equipotential surface.
59
What is escape velocity?
The minimum velocity needed to escape a gravitational field.
60
What is a synchronous orbit?
The motion of an object whose rotational period about its axis equals its orbital period.
61
What are the uses of geostationary satellites?
Transmission of TV signals and forecasting the weather.
62
What is the equation for the force on a current-carrying wire (perpendicular)?
F = BIL.
63
What is the magnitude of the emf?
The rate of change of flux linkage.
64
What is a moderator in a nuclear reactor?
A substance that slows down the fission neutrons so they can produce further fission.
65
What are control rods?
Neutron-absorbing rods that help control the rate of fission events in the reactor (e.g., Cadmium, Boron).
66
What is a coolant?
A fluid used to prevent a machine from becoming dangerously hot, transferring thermal energy to the core to a heat exchange.
67
What is the condition for holding a charged oil droplet between two oppositely charged plates?
QV/d = mg.
68
What is the terminal velocity of an oil drop?
6πnr v = mg (where f drag = weight).
69
What is the equation for the radius in Millikan's experiment?
r = sqrt(9nav/2po g).
70
What is the equation for mass in Millikan's experiment?
m = po(4/3)πr^3.
71
What is the significance of Millikan's results?
He found that the charge of an oil droplet was always an integer multiple of 1.6x10^-19, showing that electric charge is quantised in whole number multiples of 1.6x10^-19C.
72
What is Stokes' Law?
An object falling through a fluid like air will experience a viscous drag force (F = 6πnr v).
73
How was the neutrino hypothesised?
Energy wasn't being conserved during beta decay, indicating another mystery particle carrying the remaining energy.
74
What is the current definition?
The rate of flow of electric charge.
75
What does 1A mean?
One coulomb of electrical charge moving past a point per second.
76
What is Boyle's Law?
For a fixed mass of gas at a constant temperature, PV = constant.
77
What is Charles' Law?
The law that states that for a fixed mass of gas at a constant pressure, V/T is constant.
78
What is the pressure law?
For a fixed mass of gas at constant volume, P/T is constant.
79
What is the equation for the number of moles?
n = m/M (where m = mass and M = molar mass).
80
What is the inverse square law?
The intensity of radiation is inversely proportional to the square of the distance from the source of radiation (I = k/x^2).
81
What are the sources of background radiation?
Cosmic rays, food and drink, buildings, X-rays.
82
How is alpha radiation absorbed?
Completely absorbed by paper and thin metal foil.
83
How is beta radiation absorbed?
Completely absorbed by about 5mm of aluminium.
84
How is gamma radiation absorbed?
Completely absorbed by several centimetres of lead or concrete.
85
What is the intensity of radiation?
Radiation energy per second divided by total area (nhf/4πr^2).
86
What is a film badge?
A radiation detection device consisting of several layers of photographic film covered with black lightproof paper, all encased in a plastic or metal holder.
87
What is the storage method for radioactive materials?
Lead-lined containers must be thick enough to stop gamma radiation and kept under 'lock and key'.
88
What are the handling precautions for radioactive sources?
Solid sources should be transferred using tongs or gloves; liquid and gas sources should be in sealed containers to prevent inhalation or ingestion.
89
What is binding energy?
The work that must be done to separate a nucleus into its constituent protons and neutrons.
90
What is mass defect?
The difference in mass between a nucleus and its separated nucleons.
91
What is nuclear fission?
The process in which a large unstable nucleus splits into two fragments that are more stable than the original.
92
What is nuclear fusion?
Making small nuclei fuse together to form a large nucleus.
93
What is critical mass?
The minimum mass of a fissionable isotope that provides the number of neutrons needed to sustain a chain reaction.
94
What is an emergency shutdown?
Designed to insert the control rods fully into the core to stop fission completely.
95
What is shielding?
Radiation-absorbing material used to decrease exposure to radiation, especially gamma rays, from nuclear reactors.
96
What is high-level waste storage?
Vitrified and stored underground in concrete bunkers.
97
What is intermediate-level waste?
Mixed with concrete then stored underground and monitored.
98
What is low-level waste storage?
Sealed in metal drums buried in large trenches.
99
What does Newton's Law of Universal Gravitation state?
The attractive force between two masses is proportional to the product of their masses and inversely proportional to the square of the distance between the centres of the two masses.
100
What is gravitational field strength?
The force per unit mass experienced by a small test mass placed in the field.
101
What is the equation for charge on the droplet?
Q = mgd/V.
102
What is the electric field strength between plates?
E = V/d.
103
How was Millikan able to measure the mass?
By measuring its terminal speed with the electric field switched off.
104
What is the significance of Young's double-slit experiment?
Light passing through double slits produces an interference pattern, demonstrating wave properties and challenging the corpuscles theory.
105
What does the number of fringes depend on?
Slit spacing; the further they are from each other, the smaller the fringe spacing; the narrower the slits, the greater the amount of diffraction.
106
What is the relationship between mass and energy?
The mass of an object increases if it gains kinetic energy, described by E=mc^2.
107
What did Bertizzo's experiments show?
The internal energy gained by the target from each electron was equal to the kinetic energy of the electron.
