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Physics Flashcards

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1
Q

What is chemical energy?

A

Energy which is obtained from fuels, foods, and chemicals in batteries.

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2
Q

What is kinetic energy?

A

Energy in a moving object.

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3
Q

What is gravitational potential energy?

A

The potential energy of an object due to it being above the ground.

(Usually transfers into kinetic energy.)

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4
Q

What is elastic potential energy?

A

The potential energy when an object is stretched or squashed.

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5
Q

What is thermal energy?

A

Energy in an object due to its temperature.

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6
Q

What is the principle of conservation of energy?

A

Energy cannot be created or destroyed.

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7
Q

What is a closed system?

A

An object or group of objects where no energy transfer takes place into or out of the system.

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8
Q

What is the equation for work done?

A

W = F s

F = Force in newtons (N)
s = Distance (m)
W = Work done in joules (J)

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9
Q

What is the equation for gravitational potential energy?

A

ΔE = m g Δh

m=Mass(kg)
g=grav. stength(N/kg)
Δh=Height change(m)
ΔE=Energy change(J)

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10
Q

What is the equation for kinetic energy?

A

E = 1/2 m v²
E = Energy (J)
m = Mass (kg)
v = Speed (m/s)

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11
Q

What is the equation for elastic potential energy?

A

E = 1/2 k e²
E = Energy (J)
k = spring constant (N/m)
e = extension

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12
Q

What is useful energy?

A

Energy which is transferred to where it is wanted in the form it is wanted in.

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13
Q

What is wasted energy?

A

Energy which is not usefully transferred.

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14
Q

What is energy dissipation?

A

When energy is transferred into the surroundings.

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15
Q

What is the equation for input energy?

A

Input energy = useful output energy + wasted energy

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16
Q

What is efficiency?

(In terms of energy.)

A

How much energy is usefully transferred, usually expressed as a percentage.

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17
Q

What is the equation for efficiency?

(In terms of energy.)

A

Efficiency = (Useful energy transferred / Total energy supplied) x 100

(x 100 for the percentage.)

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18
Q

How can machines be made more efficient?

A
  • Lubricants to reduce friction.
  • Streamlining to reduce air resistance.
  • Copper wires to minimize electrical resistance.
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19
Q

How is energy usefully transferred by:
1) A light bulb
2) An electric mixer
3) A speaker
4) A television

A

1) Light waves emitted from the filament.
2) Work done by blades of mixer.
3) Sound waves from vibrations of speaker cone.
4) Light waves and sound waves.

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20
Q

What is power?

(In terms of energy.)

A

The rate at which an appliance transferrs energy.

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21
Q

What is the unit of power?

A

Watts (W)

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22
Q

What is the equation for power?

A

P = E/t

P = power
E = Energy
t = Time

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23
Q

What is the equation for power wasted?

A

Power wasted = total power supplied - useful power output from device.

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24
Q

What is efficiency?

(In terms of power.)

A

How much power is usefully outputted.

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25
Q

What is a thermal conductor?

A

A material that allows thermal energy (heat) to move through them easily.

For example, metals.

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26
Q

What 3 factors affect the rate of thermal energy transfer through a material?

A

1) Temperature difference across the metal.
2) Thickness of the material.
3) Thermal conductivity of the metal.

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27
Q

Why do saucepans often have wooden handles?

A

Wood is a poor thermal conductor, meaning that heat from the pan won’t reach the handle.

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28
Q

Why do materials that trap air have low thermal conductivities?

A

Air is a good insulator of thermal energy, meaning that heat won’t pass through easily.

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29
Q

What is a specific heat capacity?

A

The amount of energy required to raise the temperature of 1kg of substance by 1°C.

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30
Q

What is the equation for energy needed?

(In terms of specific heat capacity.)

A

ΔE = m c Δθ

ΔE = Energy needed (J)
m = Mass (kg)
c = Specific heat capacity (J/kg)
Δθ = Change in temperature

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31
Q

Name 5 ways buildings can be insulated / heated.

(Or name as many as you can.)

A

1) Fibreglass loft insulation. Reduces rate of energy transfer through the roof.
2) Cavity wall insulation. Reduces rate of energy transfer through the walls.
3) Aluminium foil behind radiatiors. Reflects infrared radiation back into the room.
4) Double glazing windows. Reduces rate of energy transfer through the windows.
5) Thick bricks with low thermal conductivity. Reduces rate of energy transfer through outer walls.

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32
Q

How do solar panels work?

A

They absorb infrared radiation (energy) from the sun and make energy directly through this. Some solar panels however, will use the energy to heat water to create thermal energy.

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33
Q

Name 3 fossil fuels.

A
  • Oil
  • Gas
  • Coal
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34
Q

Name 2 non-renewable energy sources.

A
  • Fossil fuel
  • Nuclear fuel
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35
Q

Name 6 renewable energy sources.

(Or as many as you can)

A
  • Biofuel
  • Wind energy
  • Hydroelectricity
  • Geothermal energy
  • Solar energy
  • Wave energy
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36
Q

How is nuclear fuel created?

A

When the unstable nucleus of a uranium atom splits in two, which releases energy.

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37
Q

What are the advantages and disadvantages of nuclear power?

A

Advantages
- They do not produce greenhouse gases.
- Nuclear fuel produces more energy per kilogram than fossil fuels.

Disadvantages
- Production of nuclear waste such as fuel rods which need to be stored safely for centuries.
- An accident can make the surrounding area unsafe for years.

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38
Q

What are the advantages and disadvantages of renewable energy sources?

A

Advantages
- They will not run out and are produced fast.
- They do not produce dangerous waste.
- Mostly do not contribute to climate change.

Disadvantages
- Cannot meet the current demand for energy.
- Some sources are not available all the time.
- Some people may think that structures for these energy sources are unsightly and they can affect animal / plant life.

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39
Q

What is static electricity?

A

When two electrically insulating materials are rubbed together, causing electrons to transfer from one object to the other.

(Direction of electron transfer depends on the materials.)

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40
Q

What does a charged object have around itself?

A

An electric field.

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41
Q

When are 2 objects repelled?

A

When they have the same electric charge.

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42
Q

When are 2 objects attracted?

A

When they have opposite charges.

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43
Q

What is a charge carried by?

A

Electrons.

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44
Q

What is the unit of charge?

A

Coulombs (C)

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45
Q

What is the equation for current?

(In terms of charge and time.)

A

I = Q / t
I = Current (A)
Q = Charge (C)
t = Time (s)

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46
Q

What is the equation for charge?

(In terms of current and time.)

A

Q = I t
Q = Charge (C)
I = Current (A)
t = Time (s)

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47
Q

What does a diode do?

A

Allows current to flow in only one direction.

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48
Q

What does a cell (or battery) do?

A

Pushes electrons around a complete circuit.

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49
Q

What does a switch do when it is:
1) Open
2) Closed

A

1) Doesn’t allow current to flow.
2) Allows current to flow.

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50
Q

What does a bulb do?

A

Emits light as a signal when a current passes through it.

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51
Q

What does a light-emitting diode (LED) do?

A

Emits a light when a current passes through.

(Current can only flow in one direction through an LED.)

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52
Q

What does an ammeter do?

A

Measures the current in a circuit.

(Connected in series with the circuit.)

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53
Q

What does a fixed resistor do?

A

Limits the current at a fixed value.

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54
Q

What does a variable resistor do?

A

Allows the resistance, and therefore the current, to be varied.

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55
Q

What does a fuse do?

A

Designed to melt if the current is greater than a certain amount and therefore breaking the circuit.

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56
Q

What does a heater do?

(In a circuit.)

A

Transfers energy from an electric current to heat the surroundings.

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57
Q

What does a voltmeter do?

A

Measures potential difference (voltage) in a circuit.

(Connected in parallel.)

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58
Q

What is the equation for potential difference?

(In terms of energy and charge.)

A

V = E / Q
V = Potential difference (V)
E = Energy transferred (J)
Q = Charge (C)

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59
Q

What is resistance?

(In a circuit)

A

Opposition to current flow.

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60
Q

What is Ohm’s Law?

A

When a resistor’s current is directly proportional to its potential difference.

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61
Q

What is an ohmic conductor?

A

A component which follows Ohm’s law.

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62
Q

What does a thermistor do?

A

Decreases resistance as temperature increases and vice versa.

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63
Q

What does a light-dependent resistor (LDR) do?

A

Decreases resistance as light shining upon it gets brighter and vice versa.

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64
Q

What is the equation for resistance?

(In terms of voltage and current.)

A

R = V / I
R = Resistance (Ω)
V = Potential difference (V)
I = Current (A)

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65
Q

What is a series circuit?

A

A circuit where all components are connected one after the other.

(If there is a break anywhere, the whole circuit will break.)

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66
Q

What is a parallel circuit?

A

A circuit with 2 or more branches.

(If a component on one branch breaks, other branches will still work.)

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67
Q

What is the equation for current?

(In terms of voltage and resistance.)

A

I = V / R
I = Current (A)
V = Potential difference (V)
R = Resistance (Ω)

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68
Q

What is the equation for potential difference?

(In terms of current and resistance.)

A

V = I R
V = Potential difference (V)
I = Current (A)
R = Resistance (Ω)

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69
Q

How do you calculate the current of a circuit with multiple branches?

A

Add the current of all branches together.

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70
Q

How do you calculate total resistance in a series circuit?

A

Add the resistance of all components.

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71
Q

How do you calculate resistance in a parallel circuit?

A

Add the resistance of the reciprocal of all components in the branches. Then, reciprocate the answer to get the resistance.

For example, branches with a resistance of 2Ω, 5Ω and 10Ω would be converted into 5/10, 2/10 and 1/10 (with common demominators in the fraction.) These fractions would be added together which would be 5/10 + 2/10 + 1/10 = 8/10. The answer is the reciprocated, meaning the resistance of the parallel circuit is 10/8, which is 1.25 Ω.

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72
Q

What is a direct current?

A

A current that passes round a circuit in one direction.

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73
Q

What is an alternating current?

A

A current which repeatedly changes direction.

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74
Q

What is the frequency of the UK’s mains supply? And what does this mean?

A

50 hertz (Hz). This means that the mains current revereses its direction 50 times per second.

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75
Q

What is the equation for frequency?

(In an alternating current.)

A

Frequency = 1 / time taken for 1 cycle.

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76
Q

What colour is the live wire and what does it do?

A

It is brown and it alternates between positive and negative voltage.

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77
Q

What is the peak voltages of the live wire?

A

+325V to -325V

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78
Q

What colour is the neutral wire and what does it do?

A

It is blue and it completes the circuit back to the power supply.

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79
Q

What colour is the earth wire and what does it do?

A

It is striped green and yellow and it provides a path into the earth to avoid electric shocks.

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80
Q

What is the National Grid?

A

A system of cables and transformers which link stations to consumers.

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81
Q

What are step-up and step-down transformers?

A

A step-up transformer increases voltage from the station to the transmission cables. A step-down transformer decreases voltage for domestic use.

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82
Q

What is the potential of the neutral wire?

A

0 Volts (V)

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83
Q

What is the outer layer of a plug made of and why?

A

It is made of a stiff plastic material because it is a good insulator.

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84
Q

What are the pins of the plug made of and why?

A

They are made of brass because it is a good electrical conductor and it doesn’t rust/oxidise.

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85
Q

What is the longest pin in a plug and why?

A

The earth wire so that it connects to the socket first.

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86
Q

Why do plugs contain fuses?

A

So that if the current gets too high, the circuit will be disrupted and stopped.

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87
Q

What is the equation for power?

(In terms of energy and time.)

A

P = E / t
P = Power (W)
E = Energy (J)
t = time (s)

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88
Q

What is the equation for energy?

(In terms of power and time.)

A

E = P t
E = Energy (J)
P = Power (W)
t = time (s)

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89
Q

What is the equation for power?

(In terms of current and voltage.)

A

P = I V
P = Power (W)
I = Current (A)
V = Voltage (V)

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90
Q

What is the equation for current?

(In terms of power and voltage.)

A

I = P / V
I = Current (A)
P = Power (W)
V = Voltage (V)

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91
Q

What is the voltage of the mains supply?

A

230 Volts (V)

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92
Q

Why should the fuse current rating be slightly higher than the current through the appliance?

A

So that the fuse will melt only if the expected current is exceeded.

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93
Q

What is the equation for charge?

(In terms of current and time.)

A

Q = I t
Q = Charge (C)
I = Current (A)
t = Time (s)

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94
Q

What is the equation for energy?

(In terms of voltage and charge.)

A

E = V Q
E = Energy (J)
V = Voltage (V)
Q = Charge (C)

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95
Q

What is density?

A

Measurement of mass per unit volume, usually measured in kg/m³

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96
Q

What is the equation for density?

A

ρ = m / v
ρ = Density (kg/m³)
m = Mass (kg)
v = Volume (m³)

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97
Q

What is the alternative measurement to kg/m³ and its conversion?

A

g/cm³.
1000kg/m³ = 1g/cm³

98
Q

Order the 3 states of matter from most to least energetic.

A

1) Gas
2) Liquid
3) Solid

99
Q

What is latent heat?

A

Energy transferred to or from a substance as it changes states.

100
Q

What is internal energy?

A

The total energy in the kinetic energy and potential energy store in a substance.

101
Q

What happens to particles when temperature increases?

A

Kinetic energy increases.

(i.e. they move around faster.)

102
Q

What are the forces of attraction like in the 3 states of matter?

A

Solid: strong forces
Liquid: weak forces
Gas: negligible forces (too small to be noticed.)

103
Q

How is pressure created?

A

When gas particles collide with each other and the walls of a container. These collisions exert a force.

104
Q

What is the specific latent heat of fusion?

A

Energy needed to change 1kg of substance from solid to a liquid.

105
Q

What is the specific latent heat of vaporisation.

A

The energy needed to change 1kg of substance from liquid to vapour.

106
Q

What is the equation for latent heat of fusion and vaporisation?

A

L = E / m
L = Latent heat (J/kg)
E = Energy needed (J)
m = Mass (kg)

107
Q

What happens to pressure if a fixed mass of gass has:
1) Less space
2) More space

A

1) Pressure will increase.
2) Pressure will decrease.

108
Q

What is the relationship between pressure and volume?

A

They are inversely proportional.

109
Q

Why are some substances radioactive?

A

They have unstable nuclei, they become stable by radioactive decay where they emit radiation.

110
Q

What are the 3 types of nuclear radiation?

A

1) Alpha
2) Beta
3) Gamma

111
Q

Can rate of decay of a radiocative substance be changed manually?

A

No, it is a random process and no external conditions can affect the rate of decay.

112
Q

If most alpha particles passed through the gold foil, what does this mean for the atom?

A

Most of the atom is empty space.

113
Q

What does an alpha particle consist of?

A

2 protons and 2 neutrons.
Mass number = 4
Atomic number = 2
Charge = +2

114
Q

What does a beta particle consist of?

A

1 electron.
Mass number = 0
Atomic number = -1
Charge = -1

115
Q

What does gamma radiation consist of?

A

An electromagnetic wave released from the nucleus.
Mass number = 0
Atomic number = 0
Charge = 0

116
Q

What is ionisation?

A

When electrons are lost or gained.

117
Q

What is radioactive contamination?

A

When there are unwanted materials with radioactive atoms on other materials.

118
Q

What are the ionising powers of the 3 nuclear radiation types?

A

Alpha - Strongly ionising
Beta - Moderately ionising
Gamma - Weakly ionising

119
Q

What are the relative masses of the 3 nuclear radiation types?

A

Alpha: 4u (large)
Beta: 1/1845u
Gamma: 0u

120
Q

What are the penetrating powers of the 3 nuclear radiation types?

A

Alpha - Weak penetration
Beta - Moderate penetration
Gamma - High penetration

121
Q

What are the ranges in air of the 3 nuclear radiation types?

A

Alpha: 5cm
Beta: 1m
Gamma: Unlimited

122
Q

What are the 3 types of nuclear radiation absorbed by?

A

Alpha: Thin sheet of paper or skin.
Beta: 5mm thick aluminium sheet or 2-3mm thick lead sheet.
Gamma: Thick lead sheet.

123
Q

Where are the 3 types of nuclear radiation deflected to in an electric field?

A

Alpha: Towards negative plate.
Beta: Towards positive plate.
Gamma: No deflection.

124
Q

What is ‘activity’ of a radioactive source?

A

Number of unstable atoms in the source which decay per second.

(This is also the count rate.)

125
Q

What is half-life?

A
  • Average time it takes for the number of nuclei to halve
  • Average time it takes for count rate to halve
126
Q

What is radioactive activity measured in?

A

Becquerel (Bq)

127
Q

What is a radioactive tracer and how do they work?

A

A machine used to measure the flow of a substance through an object. The patient drinks or is injected with a radioactive isotope which emits gamma radiation. The gamma radiation is then monitored through a gamma detector.

128
Q

Why is gamma radiation usually used for medicine instead of other types of nuclear radiation?

A

It can penetrate through skin and go deep into the body.

129
Q

Why do medical tracers have half-lives of just a few hours?

A

The half-life is long enough to complete imaging but short enough to not expose the patient to unneccessary radiation.

130
Q

What is nuclear fission?

A

The splitting of an atomic nucleus into 2 smaller nuclei.

131
Q

What does nuclear fission release?

A
  • 2 or 3 high speed neutrons.
  • Energy in the form of gamma radiation and kinetic energy of the nuclei and neutrons.
132
Q

Which 2 isotopes are involved in nuclear fission?

A
  • Uranium-235
  • Plutonium-239
133
Q

What is induced fission and spontaneous fission?

A

Induced fission is when a neutron is absorbed into the nucleus and causes fission.
Spontaneous fission is when fission occurs without a neutron being absorbed, however this is rare.

134
Q

What is a chain reaction in nuclear fission?

A

When neutrons released from previous fission causes more fission events to occur.

135
Q

How is nuclear fission controlled in a nuclear reactor?

A

Control rods in the reactor core are used to absorb surplus neutrons. The height of the rods are adjusted to maintain a steady chain reaction.

136
Q

What is nuclear fusion?

A

When 2 nuclei are close enough together to form a larger nucleus.

137
Q

What process releases energy in the Sun?

A

Nuclear fusion.

138
Q

How are nuclei contained in a fusion reactor?

A

Using a magnetic field.

139
Q

What are the 2 major sources of background radiation for a person in the UK.

A

Radon gas and cosmic rays.

140
Q

Why must radioactive waste be stored safely?

A

It emits radiation which can cause cancer and have other harmful effects.

141
Q

What is a vector quantity?

A

A measurement of both magnitude and direction.

142
Q

What is a scalar quantity?

A

A measurement of magnitude but no direction.

143
Q

What is displacement?

A

Distance in a certain direction.

144
Q

What is a force?

A

A push or pull action on an object due to an interaction with another object.

145
Q

What is Newton’s third law of motion?

A

When 2 objects interact with each other, they exert equal and opposite forces on each other.

146
Q

What is the unit of force?

A

Newtons (N)

147
Q

In what way does weight force always act?

A

Downwards

148
Q

What is a resultant force?

A

The overall magnitude and direction of 2 or more forces.

149
Q

What is Newton’s first law of motion?

A

If the forces acting on an object are balanced, the resultant force is 0. Also, if an object is at rest, it will stay at rest. If an object is moving, it will maintain the same speed.

150
Q

What is a moment?

A

The turning effect of a force.

151
Q

What are moments measured in?

A

Newton metres (N m)

152
Q

What is the equation for moments?

A

M = f d
M = Moment (N m)
f = Force (N)
d = perpendicular distance from line of action to pivot (m)

153
Q

Which 2 ways can increase a moment?

A
  • Increasing the magnitude of the force.
  • Increasing perpendicular distance from the line of force to the pivot.
154
Q

What are the differences between a low and high gear?

A

Low: Low speed, high turning effect.

High: High speed, low turning effect.

155
Q

What is the centre of mass?

A

The point at which it is thought that all mass is concentrated in an object.

156
Q

What is the principle of moments?

A

If an object isn’t turning, it is at equilibrium. Both clockwise and anticlockwise moments are equal.

157
Q

What is the method used to find the magnitude and direction of 2 different forces?

A

Drawing a parallelogram proportionally with both forces.

158
Q

What is the equation for speed?

A

Speed = Distance / Time

159
Q

What does gradient on a distance-time graph represent?

A

Speed

160
Q

What is velocity?

A

Speed in a given direction.

161
Q

What is the equation for acceleration?

A

Acceleration = Change in speed / Time

162
Q

What does the gradient on a velocity-time graph represent?

A

Acceleration

163
Q

What does it mean if the gradient on a velocity-time graph is negative?

A

The object is decelerating.

164
Q

What does the area under a velocity-time graph represent?

A

Distance travelled in a given direction.

165
Q

How can you find the gradient on a curved line?

A

Drawing a tangent at a given point and calculating the gradient of the tangent.

166
Q

What is the equation to calculate a gradient.

A

Change in y / Change in x

167
Q

What is the equation for resultant force?

(In terms of mass and acceleration)

A

F = ma

F = Force (N)
m = Mass (kg)
a = Acceleration (m/s²)

168
Q

What is Newton’s second law of motion?

A

The acceleration of an object is proportional to the resultant force.
The acceleration of an object is also inversely proportional to the mass.

169
Q

What is inertia?

A

The tendancy for an object to stay at rest or at a constant speed in a straight line.

170
Q

What is the drag force when an object is falling out of the sky?

A

Air resistance

171
Q

What is stopping distance?

A

The distance a vehicle travels from reaction of the driver to being stationary.
(Stopping distance = thinking distance + braking distance)

172
Q

What is the equation for momentum?

A

p = mv

p = Momentum (kg m/s)
m = Mass (kg)
v = Velocity (m/s)

173
Q

What is the law of conservation of momentum?

A

Whenever objects interact in a closed system, the amount of momentum before the interaction is equal to the total momentum after the interaction.

174
Q

What is the equation for impact force?

A

F = mΔv / t

F = Force (N)
m = Mass (kg)
Δv = Change in velocity (m/s)
t = Time taken (s)

175
Q

What happens when 2 vehicles collide in terms of momentum?

A
  • Exert equal, but opposite forces on each other.
  • Change in momentum of one vehicle is equal and opposite to the change in momentum of the other vehicle.
  • Therefore, total momentum remains unchanged.
176
Q

What are the safety features on a modern car?

A
  • Seat belts
  • Airbags
  • Crumple zones
  • Side impact bars
177
Q

What is an elastic object?

A

An object which regains its original shape when the forces deforming it are removed.

178
Q

What is the extension of a spring?

A

The increase in a spring’s length from the original length.

179
Q

What is the relation between extension and force applied?

A

They are directly proportional.

180
Q

What is the limit of proportionality for a spring?

A

When too big of a force is applied on a spring, the graph will no longer be directly proportional.

181
Q

What is the equation for the force of a spring?

A

F = ke

F = Force (N)
k = Spring constant (N/m)
e = Extension (m)

182
Q

What is pressure measured in?

A

Pascals (Pa)
or
N/m²

183
Q

What is the equation for pressure?

A

p = F / A

p = Pressure (Pa)
F = Force (N)
A = Area (m²)

184
Q

How would pressure differ in different areas in a body of water?

A
  • Further down a liquid has a greater pressure because there is more water above pushing down.
  • A greater density of water has a greater pressure.
185
Q

How is atmospheric pressure created?

A

Air molecules in the Earth’s atmosphere collide with surfaces. Every impact creates a small force on the surface.

186
Q

How does atmospheric pressure change with altitude?

A

The lower you are, the more pressure. This is because the air is more dense and there is a greater weight of air above you.

187
Q

What is upthrust?

A

The upward force when the an object’s resultant force upwards is greater than the resultant force downwards when it is underwater. This will result in the object being pushed upwards.

188
Q

What is the upthrust force equal to?

A

The amount of water being displaced.

189
Q

How does density affect if an object will sink in water or not?

A

An object with a density greater than the water it is immersed in will sink.

An object with a density less than the water it is immersed in will float.

190
Q

What is a transverse wave?

A

A wave where the particles oscillate perpendicular to the direction of energy transfer (i.e. direction the wave is travelling in.)

191
Q

What is a longitudinal wave?

A

A wave where the particles oscillate parallel to the direction of energy transfer (i.e. direction the wave is travelling in.)

192
Q

What is a mechanical wave?

A

A wave which travels through a medium (a material.)

193
Q

What is an electromagnetic wave?

A

A wave that travels through a vacuum (or space)

194
Q

What is the amplitude of a wave?

A

The maximum height or depth of a wave from the midpoint.

195
Q

What is the wavelength of a transverse wave?

A

Distance from one point in an oscillation to the same point in the next oscillation in a wave.

196
Q

What is the frequency of a transverse wave?

A

The number of wave crests passing through a point every second, measured in hertz (Hz.)

197
Q

What is the period of a wave?

A

Time taken for one wavelength to pass a point.

198
Q

What is the equation for the period of a wave?

A

Period = 1 / frequency

199
Q

What is the equation for wave speed?

A

v = f λ

v = Wave speed (m/s)
f = Frequency (Hz)
λ = wavelength (m)

200
Q

What is the wavelength of a longitudinal wave?

A

Distance from the middle of one compression the the middle of the next compression.

201
Q

What is the frequency of a longitudinal wave?

A

Number of compressions passing through a point in one second.

202
Q

What 3 things could happen when a wave meets a boundary?

A
  • Be totally or partially reflected by the boundary
  • Transmit through the boundary
  • Be absorbed by the boundary
203
Q

How are echoes created?

A

When sound waves reflect off surfaces.

204
Q

What does change in frequency do to a sound wave?

A

Higher frequency = higher pitch

Lower frequency = lower pitch

205
Q

What does change in amplitude do to a sound wave?

A

Greater amplitude = louder sound

Smaller amplitude = quieter sound

206
Q

How do ultrasound scanners work?

A

A device called a transducer produces an ultrasound wave. When the wave meets a boundary between 2 different materials, the wave is partially reflected. The wave travels back through the material to be detected by the transducer. The time taken for the wave to return can be used to calculate how far away the boundary is. Results are processed by a computer to create an image.

207
Q

What is the ‘focus’ of an earthquake?

A

The point at which an earthquake originates from.

208
Q

What is the ‘epicentre’ of an earthquake?

A

The closest point on the Earth’s surface to the focus of the earthquake.

209
Q

What are the 4 layers of Earth?

(Order from outermost to innermost layer)

A

1) Crust
2) Mantle
3) Outer core
4) Inner core

210
Q

What does a seismometer do?

A

Detects movements in the Earth’s crust causes by seismic waves.

211
Q

What are the characteristics of seismic p-waves?

A
  • Primary seismic waves
  • Longitudinal waves
  • Quicker than s-waves
  • Refract at the boundary between the mantle and the core.
  • Speed up as depth increases (greater density lower down)
212
Q

What are the characteristics of seismic s-waves?

A
  • Secondary seismic waves
  • Transverse waves
  • Slower than p-waves
  • Bend as they travel from the focus to the mantle.
  • Cannot travel through outer core (cannot travel through liquids)
213
Q

What is a shadow zone?

A

Areas where either p-waves or s-waves don’t reach because they are refracted or absorbed.

214
Q

List all electromagnetic waves from longest wavelength to shortest wavelength

A
  • Radio waves (longest)
  • Microwaves
  • Infrared
  • Visible light
  • Ultraviolet
  • X-rays
  • Gamma rays (shortest)
215
Q

What speed do electromagnetic waves travel at?

A

300 million m/s (speed of light)

216
Q

How are colours that compose white light different from each other?

A

Different wavelengths

(Red is the longest and violet is the shortest.)

217
Q

What is infrared radiation emitted by?

A

All objects

218
Q

Which type of substances absorb and emit the most infrared?

A

Darker substances
Hotter substances also emit more infrared

219
Q

What are carrier waves?

A

Waves used to carry any type of signal

220
Q

What are the characteristics of short and long wavelengths when it comes to carrying information?

A

Shorter
- Carry more information
- Shorter range
- Less spread out

Longer
- Carry less information
- Longer range
- More spread out

221
Q

How can ultraviolet be dangerous?

A
  • Can cause sunburn
  • Can cause skin cancer
  • Can harm eyes
222
Q

How do x-rays work medically?

A

They pass through soft tissues and skin, but are absorbed by bones, teeth and metal objects that aren’t too thin. Therefore, they can be used to check for fractures and dental problems.

223
Q

What is the ‘normal’?

(To do with light rays)

A

A line perpendicular to the mirror where the incident ray hits the mirror.

224
Q

What is the angle of incidence?

A

The angle between the incidence ray and the normal

225
Q

What is the angle of reflection?

A

The angle between the reflected ray and the normal

226
Q

What is the correlation between the incidence ray and the reflected ray?

(On a flat surface)

A

They are always equal

227
Q

What is diffuse reflection?

A

Reflection from a rough surface, incident rays are reflected in different directions.

228
Q

What is refraction?

A

When any kind of wave changes direction as it changes speed at a boundary

229
Q

What is the angle of refraction?

A

The angle between the refracted ray and the normal

230
Q

What happens when light hits a:
1) Transparent object
2) Translucent object
3) Opaque object

A

Transparent: all light is transmitted.
Translucent: some light passes through, some is absorbed. The light that passes through is scattered or refracted.
Opaque: all light is absorbed

231
Q

What happens when light hits:
1) A white surface
2) A black surface
3) A coloured surface

A

White: all light is reflected
Black: all light is absorbed
Coloured: the colours in the visible light spectrum that make the colour of the surface are reflected. The rest are absorbed.

232
Q

What is the formula for specific heat capacity?

A

c = ΔE / m x Δθ
c = Specific heat capacity (J/kg °C)
ΔE = Change in energy (J)
m = Mass (kg)
Δθ = Change in temperature (°C)

233
Q

What is a zero error?

A

When a measuring instrument gives a false reading when the true value is actually zero

234
Q

What is a random error?

A

When ther is an unpredictable variation due to things you have no control over

235
Q

What is a systematic error?

A

When the measuring instrument reads a value which differs from the real value by a consistent amount each time the measurement is made

236
Q

What is the gravitational field strength of earth?

A

9.8N/kg

237
Q

Which factors can affect thinking distance?

A
  • Alcohol or drug influence
  • Caffeine
  • Distractions
  • Tiredness
  • Using a mobile phone
238
Q

Which factors can affect braking distance?

A
  • Road conditions
  • Brake conditions
  • Tyre conditions
  • Poor weather
239
Q

How is impact force decreased?

A
  • Increase stopping time
  • Decrease rate of momentum change
  • Decreases force
240
Q

How is impact force increased?

A
  • Decrease stopping time
  • Increase rate of momentum change
  • Increases force

GCSE (11 decks)

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