Lower Remove End-of-Year Physics Revision Flashcards
1
Q
What are the energy stores?
A
The energy stores are chemical, elastic potential, electrostatic, gravitational potential, kinetic, light, magnetic, nuclear, and thermal.
2
Q
What is chemical energy?
A
Chemical energy is energy stored in batteries, foods, and fuels.
3
Q
What is elastic potential energy?
A
Elastic potential energy is energy stored in an extended or compressed object.
4
Q
What is electrostatic energy?
A
Electrostatic energy is energy stored in objects that have opposite charges.
5
Q
What is gravitational potential energy?
A
Gravitational potential energy is energy stored in an object above the ground.
6
Q
What is kinetic energy?
A
Kinetic energy is energy stored in a moving object.
7
Q
What is light energy?
A
Light energy is energy stored in an object that gives off light.
8
Q
What is magnetic energy?
A
Magnetic energy is energy stored in a magnet or magnetic field.
9
Q
What is nuclear energy?
A
Nuclear energy is energy stored in the nucleus of an atom.
10
Q
What is thermal energy?
A
Thermal energy is energy stored in an object, depending on how hot or cold it is.
11
Q
What is an energy transfer?
A
An energy transfer is the conversion of one form or energy to another, or the movement of energy from one place to another.
12
Q
What are the 4 energy transfers?
A
The four energy transfers are:
Mechanically - energy transferred by forces
Electrically - energy transferred by a current in a circuit.
Heating - energy transferred by conduction and convection (heating and cooling).
Radiation - energy transferred by light and sound.
13
Q
What does the Law for the Conservation of Energy state?
A
The Law for the Conservation of Energy states that energy can’t be created or destroyed, it can only be transferred.
14
Q
What is a system?
A
A system is an object or group of objects.
15
Q
What happens when a system changes?
A
When a system changes, the energy stored in that system changes as well, as it’s transferred from one store to another.
16
Q
What is energy efficiency?
A
Energy efficiency is how much of the total energy an object was provided with was used was for the object’s purpose.
17
Q
What is efficiency a good measure of?
A
Efficiency is a good measure of how good a device is at changing energy from one form to another.
18
Q
What is wasted energy?
A
Wasted energy is energy that is transferred to unwanted forms.
19
Q
Where is wasted energy usually transferred to?
A
Wasted energy is transferred to the thermal energy store of the surroundings.
20
Q
What is the formula for energy efficiency?
A
efficiency = useful energy output ÷ total energy input x 100%
21
Q
What are the rules of Sankey diagrams?
A
The rules of Sankey diagrams:
1) The thickness of the arrow relates to the amount of energy. The thicker the arrow, the more energy there is.
2) The total thickness of all of the arrows must stay the same.
3) The wasted energy arrow always points downwards.
4) The types of energy should be identified.
22
Q
What is the formula for work done?
A
Formula for work done: W = F x d
W = work done - measured in Joules (J)
F = force - measured in Newtons (N)
d = distance moved - measured in metres (m)
23
Q
What is work done the same as?
A
Work done is the same as energy transferred.
24
Q
What is the formula for gravitational potential energy?
A
Formula for gravitational potential energy: Eg = m x g h x h
Eg = gravitational potential energy - measured in Joules (J)
m = mass - measured in kilograms (kg)
g = gravitational field strength - measured in Newtons per kilogram (N/kg)
h = height - measured in metres (m)
25
What is the formula for kinetic energy?
Formula for kinetic energy: Ek = 0.5 x m x v^2
Ek = kinetic energy - measured in Joules (J)
m = mass - measured in kilograms (kg)
v = velocity - measured in metres per second (m/s)
26
What is power?
Power is the rate of the transfer of energy or the rate of doing work.
27
What is the formula for power?
Formula for power: P = W (or E) ÷ t
P = power - measured in Watts (W)
W / E = work done / energy transferred - measured in Joules (J)
t = time - measured in seconds (s)
28
What are the renewable energy sources?
The renewable energy sources are biomass, geothermal, hydropower, solar, and wind.
29
What are the non-renewable energy sources?
The non-renewable energy sources are coal, natural gas, nuclear, and oil.
30
What do waves do?
Waves transfer energy from one place to another.
31
What are the two types of wave?
The two types of wave are longitudinal and transverse.
32
In what direction are the vibrations in longitudinal waves?
In longitudinal waves, the vibrations are parallel to the direction of wave travel.
33
In what direction are the vibrations in transverse waves?
In transverse waves, the vibrations are at right angles (perpendicular) to the direction of wave travel.
34
What is the amplitude of a wave?
The amplitude is the height of a wave.
35
What is the crest of a wave?
The crest is the top of a wave.
36
What are two other names for the crest of a wave?
Two other names for the crest of a wave is wavefront and peak.
37
What is the trough of a wave?
The trough is the bottom of a wave.
38
What is the frequency of a wave?
The frequency of a wave is a measure of how many waves travel past a point every second.
39
What is the wavelength of two waves?
The wavelength is the distance between two waves.
40
What is the time period of a wave?
The time period of a wave is how long it takes a wave to travel the wavelength.
41
What is compression of a wave?
The compression is a region in a wave where the particles are closest together.
42
What is rarefaction in a wave?
Rarefaction is a region in a wave where the particles are farthest apart.
43
What do waves transfer without transferring matter?
Waves transfer energy and information without transferring matter.
44
What is the formula for wave speed?
Formula for wave speed: v = f x λ
v = wave speed - measured in metres per second (m/s)
f = wave frequency - measured in Hertz (Hz)
λ = wave length - measured in metres (m)
45
What is the formula for wave frequency?
Formula for wave frequency: f = 1 ÷ T
f = wave frequency - measured in Hertz (Hz)
T = time - measured in seconds (s)
46
What is the Doppler Effect?
The Doppler Effect, also known as the Doppler Shift, is the change in the frequency and wavelength of a sound wave when the source of the sound wave is moving relative to an observer.
47
What does an observer experience in terms of frequency and wavelength when the source of a sound wave is nearby?
When the source of a sound wave is nearby to the observer, they experience a short wavelength and a high frequency.
48
What does an observer experience in terms of frequency and wavelength when the source of a sound wave is far away?
When the source of a sound wave is far away from the observer, they experience a long wavelength and a low frequency.
49
What does the Big Bang Theory suggest?
The Big Bang Theory suggests that the Universe began from a very small region that was very hot and dense, and then it exploded outwards to form the Universe.
50
What is the red-shift?
The red-shift is when the wavelength of light from the most far-away galaxies is increased. It is the main evidence for the Big Bang Theory as it shows that the Universe is expanding.
51
What can happen to a wave travelling from one object to another?
A wave travelling from one object to another can be transmitted (transmission), reflected (reflection), refracted (refraction), diffracted (diffraction), absorbed (absorption), and scattered (scattering).
52
What is transmission?
Transmission is when a wave travels through an object in a straight line.
53
What is diffraction?
Diffraction is when a wave travels through an object and it spreads out evenly into more waves.
54
What is absorption?
Absorption is when a wave travels through an object and no long travels in a straight line, instead in a zig-zag pattern.
55
What is scattering?
Scattering is when a wave hits an object and reflects off of it in random directions.
56
What is reflection?
When a wave hits an object and bounces back at the same angle.
57
What is the Law of Reflection?
Law of Reflection: angle of incidence (i°) = angle of reflection (r°)
58
What is the normal of a wave?
The normal of a wave is the line perpendicular to the surface that the wave is reflecting off.
59
What is the point of incidence?
The point of incidence is where a wave hits a surface.
60
When does a wave refract towards the normal?
When a wave travels into an object that has a higher refractive index it refracts towards the normal (refraction) and when it leaves the object it returns back to its original angle.
61
What happens to a wave in a more dense material?
In a more dense material, the wave travels more slowly, meaning the wavelength decreases.
62
What is the constant speed of light?
The constant speed of light is 300,000km/s.
63
What type of wave travels at the speed of light?
Electromagnetic waves travel at the speed of light.
64
What is the electromagnetic spectrum?
The electromagnetic spectrum is a family of 7 transverse waves.
65
What is the order of the electromagnetic spectrum in terms of decreasing wavelength, but increasing frequency, energy, and hazard?
Order of the electromagnetic spectrum:
Radio waves
Microwaves
Infrared
Visible light
Ultraviolet
X-rays
Gamma rays
66
What is the order of visible light (colours of a rainbow)?
Order of visible light: red, orange, yellow, green, blue, indigo, and violet.
67
What are the three electromagnetic waves with the most energy and are therefore ionising?
Ionising waves:
Gamma rays
X-rays
Ultraviolet
68
What are gamma rays used for?
Gamma rays are used for sterilising food and medical equipment, and killing cancer cells (radiotherapy).
69
What are the risks of using gamma rays?
The risks of using gamma rays are they are ionising so can damage or mutate cells and cause cancer.
70
What are the uses of X-rays?
The uses of X-rays are observing the internal structures of objects and materials (imaging luggage and X-raying bones).
71
What are the risks of X-rays?
The risks of X-rays are they are ionising so can damage or mutate cells and cause cancer.
72
What are the uses of ultraviolet light?
The uses of ultraviolet light are in fluorescent lamps, sun beds, and security marking.
73
What are the risks of ultraviolet light?
The risks of ultraviolet light are damage to surface cells (sunburn), and they are ionising so can damage or mutate cells and cause cancer.
74
What are the uses of visible light?
The uses of visible light are seeing, fibre-optic communication, endoscopes, and photography.
75
What are the risks of visible light?
The risks of visible light are blindness.
76
What are the uses of infrared?
The uses of infrared are heating, night vision equipment, and remote controls.
77
What are the risks of infrared?
The risks of infrared are skin burns.
78
What are the uses of microwaves?
The uses of microwaves are cooking, satellite communication, and mobile phones.
79
What are the risks of microwaves?
The risks of microwaves are internal heating of body tissue.
80
What are the uses of radio waves?
The uses of radio waves are broadcasting (radio and television) and communication.
81
What are circuit symbols used to show?
Circuit symbols are used to show different components of an electrical circuit.
82
Learn the circuit symbols.
Learn the circuit symbols.
83
What is a series circuit?
A series circuit is a circuit that follows one single loop.
84
What is a parallel circuit?
A parallel circuit is a circuit that follows more than one loop.
85
When will parts of a circuit work?
Parts of a circuit will work if there is a complete circuit.
86
What is an incomplete circuit?
An incomplete circuit is a circuit that has a break in it.
87
What do charged particles (electrons) flow through?
Charged particles (electrons) flow through metal wires.
88
What is the unit of charge?
The unit of charge is Coulombs (C).
89
What is the charge of each electron?
The charge of each electron is -1.6 x 10^-19 Coulombs.
90
What is current?
Current is the rate of flow of charge (how much charge is flowing every second).
91
What is the unit of current?
Current has units of Amperes (A).
92
What is current measured by?
Current is measured by an ammeter.
93
What kind of circuit does an ammeter go in?
An ammeter goes in a series circuit.
94
What is the formula for charge?
Formula for charge: Q = I x t
Q = charge - measured in Coulombs (C)
I = current - measured in Amperes (A)
t = time - measured in seconds (s)
95
What is potential difference?
Potential difference is a measure of how much energy is transferred to or by each Coulomb of charge.
96
What is another name for potential difference?
Another name for potential difference is voltage.
97
What is the unit of potential difference?
Potential difference has units of Volts (V).
98
What is used to measure potential difference?
A voltmeter is used to measure potential difference.
99
What kind of circuit does a voltmeter go in?
A voltmeter goes in a parallel circuit.
100
What is the formula for energy transferred?
Formula for energy transferred: E = Q x V
E = energy transferred - measured in Joules (J)
Q = charge - measured in Coulombs (C)
V = voltage - measured in Volts (V)
101
Learn the metric system prefixes.
Learn the metric system prefixes.
102
What is resistance?
Resistance is a measure of how hard it is for the current to pass through a component in a circuit.
103
What does Ohm's Law state?
Ohm's Law states that the current through a resistor is proportional to the voltage, provided that the temperature is constant.
104
What is the formula for voltage?
Formula for voltage: V = I x R
V = voltage - measured in Volts (V)
I = current - measured in Amperes (A)
R = resistance - measured in Ohms (Ω)
105
What is electrical power?
The electrical power supplied to an appliance is the energy transferred to the appliance each second.
106
What is the unit of power?
Power has units of Watts (W).
107
What is the formula for power?
P = I x V
P = power - measured in Watts (W)
I = current - measured in Amperes (A)
V = voltage - measured in Volts (V)
108
What happens when an electric current passes through a resistor?
When an electric current passes through a resistor, the power supplied to the resistor heats it, and energy is dissipated to the surroundings.
109
What happens to current in a series circuit?
In a series circuit the current flows through one continuous path. This means that the current must be the same at all parts in a circuit.
110
What happens to current in a parallel circuit?
In a parallel circuit, there are different paths for the current to take, therefore the current splits.
111
What happens to voltage in a series circuit?
In a series circuit the voltage supplied by the battery is shared by the components, so the sum of the voltage across the components equals the battery voltage.
112
What happens to voltage in a parallel circuit?
In a parallel circuit the voltage across each bulb is the same as the voltage across the battery.
113
What happens to the resistance of a thermistor as the temperature increases?
When the temperature increases, the resistance of a thermistor decreases.
114
What happens to the resistance of an LDR when the light intensity increases?
When the light intensity increases, the resistance of an LDR decreases.
115
What happens in a circuit when the light level increases?
When the light level in a circuit increases:
1) Resistance across the LDR will decrease.
2) Voltage across the LDR will decrease.
3) Voltage across the resistor increases.
4) Overall current in the circuit increases.
116
What are sensing circuits used in?
Sensing circuits are used in central heating that turns on automatically when it's cold, and in lighting circuits that turn on when it's dark.
117
What are the two types of current?
The two types of current are direct current and alternating current.
118
What is direct current?
Direct current (d.c.) only flows in one direction. It is usually powered by a battery.
119
What is alternating current?
Alternating current (a.c.) constantly changes direction. It is plugged into a socket.
120
What is the alternating current voltage and frequency of mains electricity?
Mains electricity has 230V of alternating current with a frequency of 50Hz.
121
What are the names, colours, and uses of the three wires of a three-pin plug?
Live wire (brown) - carries the alternating current.
Neutral wire (blue) - completes the circuit.
Earth wire (green and yellow) - safety wire.
122
When does an appliance need an Earth wire for safety?
An appliance needs an Earth wire for safety when it has a metal casing.
123
Why does an appliance with a plastic casing not need an Earth wire?
An appliance with plastic casing doesn't need an Earth wire because it's double-insulated.
124
What is the correct size of a fuse?
The correct size of a fuse is one that is slightly above the regular operating current.
125
What is the largest domestic fuse size and what is it used for?
The largest domestic fuse size is 13A and it is reserved for high-power devices like electric radiators.
126
What is a circuit breaker?
A circuit breaker is a resettable switch that will trip if too large a current is flowing.
127
What does a step-up transformer do?
A step-up transformer increases voltage but decreases current.
128
What does a step-down transformer do?
A step-down transformer decreases voltage but increases current.
129
What is the National Grid?
The National Grid is a network of cables that distributes electricity from power stations to houses and other buildings.
130
What is the voltage of the National Grid?
The National Grid's voltage is about 132,000V.
131
What is high voltage used for?
High voltage is used to reduce power losses and make the system more efficient.
132
What does high voltage mean in terms of current and power supplied?
High voltage means that the current can be lower for the same power supplied.
133
What is the journey of electricity?
Power station ➞ step-up transformers ➞ high-voltage transmission lines ➞ step-down transformers ➞ consumers
134
At what voltage do power stations provide electricity?
Power stations provide electricity at a voltage of 25,000V.
135
What do step-up transformers do with the voltage from power stations?
Step-up transformers are used to step the voltage from power stations up to the grid voltage.
136
What do step-down transformers do with the voltage from power stations?
Step-down transformers are used to step the grid voltage down to 230V for use in homes and other buildings.
137
What is density?
Density is how much mass there is in a given volume.
138
What is the formula for density?
Formula for density: D (or ρ) = M ÷ V
D (or ρ) = density - measured in grams per centimetres cubed (g/cm^3)
M = mass - measured in grams (g)
V = volume - measured in centimetres cubed (cm^3)
139
Why do objects float?
Objects float because if they are less dense than water, meaning they have less mass than the same volume of water.
140
What is pressure?
Pressure is the amount of force acting per unit area.
141
What is the formula for pressure of solids?
Formula for pressure on solids: P = F ÷ A
P = pressure - measured in Pascals (Pa)
F = force - measured in Newtons (N)
A = area - measured in square metres (m^2)
142
In what direction does pressure in a liquid act?
Pressure in a liquid acts in all directions.
143
Does pressure in a liquid increase or decrease with depth?
Pressure in a liquid increases with depth.
144
What is the formula for pressure in a liquid?
Formula for pressure in a liquid: P = h x ρ x g
P = pressure - measured in Pascals (Pa)
h = height of column - measured in metres (m)
ρ = density of liquid - measured in kilograms per metres cubed - (kg/m^3)
g = gravitational field strength - measured in Newtons per kilogram (N/kg)
145
What is upthrust?
A force experienced by a partially or totally submerged object when there is greater pressure on the bottom surface than on the top surface.
146
Does the number of air molecules increase or decrease the higher you are and why is this?
The number of air molecules decreases the higher you go. This is because as height increases there's always less air molecules above a surface than there is at a lower height. Therefore, atmospheric pressure decreases with an increase in height.
147
What is a manometer?
A manometer is a scientific instrument used to find the pressure of a gas. The difference in the level in each side of the tube gives the difference in pressure on each side.
148
What is our solar system made up of?
Our solar system is made up of 1 star (the Sun) and 8 planets that all orbit the Sun.
149
What galaxy is our Solar System in?
Our Solar System is in the Milk Way galaxy.
150
What is a galaxy?
A galaxy is a large collection of billions of stars.
151
What is the Universe?
The Universe is a large collection of billions of galaxies.
152
What is a nebula?
A nebula is a cloud of dust and gas (helium and hydrogen) that gets pulled together under gravity.
153
What does friction do to the gases in a nebula?
Friction heats the gases in a nebula up until the nebula is hot enough for nuclear fusion to happen.
154
What does nuclear fusion involve?
Nuclear fusion involves small nuclei joining together to form larger ones.
155
What does nuclear fusion in a star involve?
Nuclear fusion in a star involves the combination of lighter isotopes of hydrogen to form helium, and the release of energy:
2, 1 H + 1, 1 H ➞ 3, 2 He + energy
156
What must happen for a nuclear fusion reaction to start?
To start a nuclear fusion reaction the fuel must be heated to 150 million degrees Celsius. This makes it into plasma which is a gas where the electron has been stripped from its nuclei.
157
What does nuclear fusion lead to and what is it converted into?
Fusion leads to a loss of mass, and this mass is converted into energy using the equation E=mc^2.
158
What does the force due to gravity depend on?
The force due to gravity depends on the mass of both objects and the distance between the objects.
159
What does gravity cause?
Gravity causes satellites (both artificial and natural) to orbit planets, and planets and comets to orbit the Sun.
160
What is the acceleration due to gravity on Earth?
The acceleration due to gravity on Earth is 9.81 m/s^2.
161
What is the formula for orbital speed?
Formula for orbital speed: π x d ÷ t
162
What is a satellite?
A satellite is something in orbit around a planet.
163
What are the two types of satellite?
The two types of satellite are natural and artificial satellites.
164
How long does it take a geostationary satellite to orbit the Earth and what are they used for?
Geostationary satellites are used for communication and it takes them 24 hours to orbit the Earth.
165
How long does it take a monitoring satellite to orbit the Earth and what are they used for?
Monitoring satellites are used for weather forecasting and and it takes them 2-3 hours to orbit the Earth. They usually orbit the Earth lower than geostationary satellites.
166
What kind of orbit does a comet have?
Comets have an elliptical orbit (oval orbit).
167
When do comets travel the fastest?
Comets travel the fastest when they are close to the Sun.
168
What is the life cycle of a star?
When a star is formed it’s stable because the forces within it are balanced. Gravity acts inwards, which is balanced by the outward force of the radiation from nuclear fusion trying to make the star expand.
169
What is the diagram for the life cycle of a star?
star-forming nebula ➞ protostar ➞
1) main sequence star with low mass ➞ red giant ➞ planetary nebula ➞ red giant
2) main sequence star with high mass ➞ red supergiant ➞ supernova ➞
1) black hole
2) neutron star
170
What is produced in a supernova?
Elements heaver than iron are produced in a supernova.
171
How are the elements produced in a supernova spread throughout the Universe?
The explosion of a massive star (supernova) spreads out the elements made in a supernova throughout the Universe.
172
What is luminosity?
Luminosity is the amount of light emitted per second by a star.
173
What is the luminosity of the Sun?
The luminosity of the Sun is about 4 x 10^26 Watts.
174
Do hotter objects emit light at short or longer wavelengths?
Hotter objects emit more light at shorter wavelengths.
175
How are stars classified?
Stars are classified by their colour.
176
What is the colour of a star linked to and how do you know whether a star is hot or cold?
The colour of a star is linked to its temperature. The hottest stars are blue and the coolest stars are red.
