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UK GCSE Physics > Energy (P1) > Flashcards

Energy (P1) Flashcards

1
Q

What are the 8 energy stores?

A 
Thermal 
Kinetic
Gravitational Potential
Elastic Potential
Chemical
Magnetic
Electrostatic
Nuclear
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2
Q

What are the 4 ways of transferring energy?

A 
Mechanically (by a force doing work)
Electrically (work done by moving charges)
By Heating (light)
By Radiation (sound)
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3
Q

For a gas, what is the internal energy store?

A

The same as a thermal store

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4
Q

What is a system?

A

The object(s) that you’re intrested in

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5
Q

What happens when a system changes?

A

Energy is transferred

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6
Q

Where is energy in a system transferred?

A

Into the system
Away from the system
Between different objects
Between different energy stores

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7
Q

What is a closed system?

A

A system wherer neither matter nor energy can leave

Net change in the total energy of a closed system is always 0

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8
Q

What are the two ways of transferring energy within a system?

A

Heating

Work Done

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9
Q

Boiling water in a kettle is an example of energy transfer by…?

A

Heating

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10
Q

What happens to energy as an object speeds up?

A

Energy is transferred to its kinetic energy store

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11
Q

What happens to energy as an object slows down?

A

Energy is transferred away from its kinetic energy store

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12
Q

What is the equation for Kinetic Energy?

A 
E = 1/2mv²
(J) = 1/2 x (kg) x (m/s)² 
Energy = 1/2 x mass x velocity²
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13
Q

What happens to g.p.e as an object is lifted higher?

A

More energy is transferred to the store

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14
Q

What effects gravitational potential energy (g.p.e)?

A

Mass, height and gravitational field strength

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15
Q

What is the equation for Gravitational Potential Energy?

A 
E = mgh
(J) = (kg) x (N/kg) x (m)
Energy = Mass x Gravitational Field Strength x Height
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16
Q

What happens to the energy stores when an object falls?

A

The energy is transferred from the gravitaional potential store to the kinetic store

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17
Q

What happens to the energy stores when an object is stretched or squashed?

A

Energy is transferred to its Elastic Potential Energy Store

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18
Q

What is the exception for elastic potential energy?

A

When the limit of proportionality is exceeded

disfiguring the object permanently

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19
Q

What is the equation for Elastic Potential Energy?

A 
E = 1/2ke²
(J) = 1/2 x (N/m/) x (m)²
Energy = 1/2 x spring constant x extension ²
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20
Q

What is Specific Heat Capacity?

A

The amount of energy needed to warm 1kg of a substances by 1°C

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21
Q

What equation links specific heat capactity and energy transferred?

A

∆E = mc∆θ
(J) = (kg) x (J/kg°C) x (°C)
ENergy transferred = Mass x Specific Heat Capacity x Change in temperature

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22
Q

How do we investigate Specific Heat Capacity (using a solid)?

A

Take a block of material with two holes
Measure the mass of the block
Wrap the block in insulation
Place a thermometer and a heater into the block
Hook up to a power supply and measure the initial temperature
Have the potential difference set to 10V
Power on and start a stopwatch
Measure temperature and current every 10 minutes (current should not change)
Use these measurments to calculate Specific Heat Capacity

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23
Q

How do I work out Specific Heat Capacity during an investigation into it?
Think about which units you have

A

You set potential difference at the start
You took measurments for current
You took measurments for tempreature
You took measurments for mass
You timed the process
Use pd and current to calculate power (P=IV)
Use power and time to calculate energy transferred (E=Pt)
Calculate the change in temperature
Use the equation ∆E = mc∆θ

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24
Q

What is the principle of conservation of energy?

A

Energy can be transferred usefully, stores or dissipated but can NEVER be created or destroyed

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25
Q

Define Power

A

Rate of energy transfer

Rate of doing work

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26
Q

What is Power measured in?

A

Watts

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27
Q

What are Watts equivilent to?

A

1W = 1J of energy transferred /second

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28
Q

How do we calculate power?

A 
P= E/t
Power = Energy (or work done) / time
(W) = (J) / (s)
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29
Q

What does it mean if a machine is powerful?

A

One that can transfer a lot of energy in a short period of time.

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30
Q

Define Conduction

A

The process where vibrating particles transfer energy to neighbouring particles

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31
Q

Define Convection

A

When energetic particles move away from hotter to cooler regions (liquids and gasses)

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32
Q

How does conduction work?

A

As the particles have a lot of thermal energy it is shared into the kinetic store causing the particles to vibrate and collide more, transferring energy

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33
Q

Thermal conductivity is the…

A

…measure of how quickly energy is transferred through a material via conduction

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34
Q

In which states of matter can convection occur?

A

Gas and Liquid states

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35
Q

Why does convection not work with solids?

A

The particles aren’t free to move

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36
Q

How does convection work?

A

As the substance warms it rises straight up
The further from the heat source the cooler and thus it begins to fall
However there is a strong currrent upwards that forces the cooling particles to a side before allowing them to fall
This creates a circular current

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37
Q

Why do we lubricate (in terms of energy use)?

A

When things move they cause friction and energy is lost as thermal, lubricating mitigates this

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38
Q

What are the main ways homes prevent energy losses through heating?

A

Thick walls
Walls made from materials with low thermal conductivoty
Thermal insulation

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39
Q

What are the different forms of thermal insulation in a house?

A

Cavity Walls
Loft Insulation
Draught excluders
Double-glazed windows

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40
Q

How do air gaps (such as with cavity walls and double glazed windows) prevent loss of thermal energy?

A

Reduces the amount of energy lost though conduction as convection (transfer of heat as a gas) must occur between the two windows/ walls and this is slower than conduction

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41
Q

How do we investigate the effectivness of thermal insulators?

A

Heat water and pour into a sealable container with different materials around it
Seal for 5 minutes and measure the temperature change for different materials

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42
Q

Define Kinetic energy

A

Energy stored in moving objects

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43
Q

How much kinetic energy is there in a stationary object?

A

None

44
Q

Define Elastic Potential Energy

A

The energy stored after we have put energy in to stretch a spring

45
Q

What is an extension?

A

How much longer the spring is due to a force being applied

46
Q

Until the limit of proportionality, the force applied to a spring and the extension have what relationship?

A

Directly Proportional

47
Q

What is the limit of proportionality?

A

A point after which a spring will not return back to its original shape even if the force is taken off.

48
Q

Define Gravitational Potential Energy

A

Gravitational potential energy is the energy stored in an object due to its position above the Earth’s surface

49
Q

What causes Gravitational Potential Energy?

A

Gravity

the force between us and the Earth

50
Q

What is the energy store at the top of a pendulums movement?

A

Gravitational Potential Energy

51
Q

What is the energy store as the pendulum moves?

A

Kinetic Energy

52
Q

What is the problem with using a pendulum as an example of a closed system?

A

There is friction between the air and pendulum

There is friction at the fixed point

53
Q

What does friction cause?

A

Energy to be transferred to thermal energy stores which are dissipated

54
Q

How can we reduce unwanted energy transfers in the pendulum model?

A

Reduce Friction

  • Use lubricant oil at the fixed point
  • Remove air particles from around the pendulum
55
Q

Define Work Done

A

Work is done whenever energy is transferred from one store to another

56
Q

What are the two types of Work Done?

A

Mechanical work

Electrical work

57
Q

How do we calculate Work Done?

A

Work Done (J) = Force (N) x Distance (m)

58
Q

Define Power

A

Power is the rate at which energy is transferred or the rate at which work is done

59
Q

What are the 2 equations for power?

A

Power (W) = Energy transferred (J) / Time (s)

Power (W) = Work Done (J) / Time (s)

60
Q

1 watt is an energy transfer of….

A

…1 joule per second

61
Q

Define Efficiency

A

What fraction of the energy we put into an appliance is tranfered to useful energy

62
Q

What are the two efficiency equations?

A 
Efficiency = Useful output energy transfer / Total input energy transfer
Efficiency = Useful power output / Total power input
63
Q

What two factors effect the cooling of a building?

A

Thermal Conductivity

Thick Walls

64
Q

What happens as thermal conductivity increases?

A

Rate of energy transfer by conduction across the material increases

65
Q

What do builders pack into wall cavities and why?

A

Insulating Material with low thermal conductivity to lower energy loss

66
Q

Why does double glazing help lower thermal conductivity?

A

Energy transfer via convection is less efficient than energy transfer by conduction.

67
Q

How can we lower thermal conductivity in a house?

A

Loft Insulation
Insulation in wall cavity
Double glazing

68
Q

When investigating Specific Heat Capacity, why is it important to wrap the beaker in insulation?

A

To lower thermal energy loss to the surroundings

69
Q

What readings do we need when investigating Specific Heat Capacity?

A

Joules (joulemeter)
Initial temperature
Final temperature
Mass

70
Q

What are the sources of inaccuracy when investigating specific heat capacity?

A

Thermal energy passes out into the air
Not all thermal energy transferred to the material
Incorrect reading of thermometer

71
Q

How can we lower the thermal energy passing out into the air when investigating specific heat capacity?

A

Insulation

72
Q

How can we prevent not all thermal energy transferred to the material when investigating specific heat capacity?

A

Ensure the immersion heater is fully submerged

73
Q

How can we prevent incorrect reading of a thermometer when investigating specific heat capacity?

A

Use a digital thermometer

74
Q

How do we investigate thermal insulators?

A

Place a small beaker in a larger one
Boil some water and transfer 80cm^3 into the small beaker
Put a cardboard lid with a hole for a thermometer over the large beaker
Record the starting temperature and start a stop watch, record the temperature every 3 minutes for 15 minutes
Repeat using the same masses of different materials

75
Q

What is the independent variable when investigating the effect of different insulators?

A

The insulator used

76
Q

Define independent variable

A

The variable we change

77
Q

Define dependent variable

A

The variable that is measured for each change in the independent variable

78
Q

What is the dependent variable when investigating the effect of different insulators?

A

Temperature

79
Q

Define Control Variable

A

Variables that are not changed throughout the experiment

80
Q

What is the control variables when investigating the effect of different insulators?

A

Starting temperature

Mass of water

81
Q

How do we investigate how the thickness of a material affects thermal insulation?

A

Start with a beaker of 80cm^3 of boiling water, with a cardboard lid
Take temperature readings every 3 minutes for 15 minutes
Repeat with 2 layers of newspaper around the beaker and then again with 4 layers and 6 layers

82
Q

What are the three main uses for energy?

A

Transport
Generating electricity
Heating

83
Q

What are the three main fossil fuels?

A

Coal
Oil
Gas

84
Q

What are the advantages of fossil fuels?

A 
Reliable (energy is there when we need it)
Release a lot of energy
Abundant
Cheap
Versatile (can be used for many things)
Portable
85
Q

What are the disadvantages of fossil fuels?

A

Release Carbon Dioxide (contributes to climate change)
Non-renewable (will eventually run out)
Release other pollutants (often dangerous)

86
Q

Why is nuclear power non-renewable?

A

Runs of uranium and plutonium

87
Q

What are the advantages of nuclear power?

A

Does not produce carbon dioxide

Extremely reliable

88
Q

What are the disadvantages of nuclear power?

A 
Highly radioactive (dangerous if exposed)
Decommissioning (at the end of the plants life) them is very long and expensive
Radioactive waste has to be stored for thousands of years before it is safe
89
Q

Why did the UK use almost only coal until the 1950s?

A

Abundant reserves

90
Q

Why did were we producing as much electricity from burning gas as from coal by 2000?

A

Abundant supplies of coal

Also had supplies of gas in the North Sea

91
Q

Why may gas be chosen over oil?

A

Releases less CO2

More flexible

92
Q

What does it mean of a power source is flexible?

A

It can be switched on quickly during periods of high demand

93
Q

What percentage of our electricity comes from wind?

A

11%

94
Q

What is the largest disadvantage of renewables?

A

Non reliable

95
Q

Why is nuclear power a good baseload?

A

The stations are difficult to power up or down

96
Q

What is a baseload?

A

Constant supply of electricity that is on all the time

97
Q

Why will we need a baseload if we use more renewable enrergy?

A

It is not very reliable

98
Q

What may be needed so that we can use more renewable energy?

A

Nuclear baseload

Gas fired power stations to provide emergency power at peak demand

99
Q

Define Renewable Energy Resources

A

A renewable energy resource is one that is being (or can be) replenished as it is used

100
Q

Name some Renewable energy resources

A 
Solar - more common
Wind - more common
Hydroelectric - more common
Tidal
Biofuel
Geothermal
Wave
101
Q

What are the two main advantages of renewables?

A

Never run out

Once in place they will not contribute to climate change

102
Q

Why are wind and solar power low in reliability?

A

Depend on changing weather conditions

103
Q

What is the disadvantage of hydroelectric power?

A

Needs abundant rivers

Damages habitats

104
Q

What is the disadvantage of tidal power?

A

Harmful to wildlife

Very small scale and experimental

105
Q

What is the disadvantage of biofuels?

A

They still release CO2 into the atmosphere, however as they come from plants they are technically carbon neutral
May increase crop prices due to need for land

UK GCSE Physics (7 decks)

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