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Physics > Energy (paper1&2) > Flashcards

Energy (paper1&2) Flashcards

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1
Q

What type of energy is stored in batteries, food and fuel?

A

Chemical energy

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2
Q

What type of energy is stored in moving objects?

A

Kinetic energy

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3
Q

What type of energy is stored in hot objects

A

Thermal energy

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4
Q

What type of energy is stored in stretched, squashed or twisted material?

A

Elastic potential energy

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5
Q

What type of energy is stored in objects in a high position

A

Gravitational potential energy

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6
Q

What type of energy is stored in atoms

A

Atomic energy or nuclear energy

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7
Q

How is energy transferred

A

It changes from one type of energy to another

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8
Q

What is the law of conservation of energy

A

It can not be created or destroyed

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9
Q

What is a ‘system’

A

Something in which we are studying

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10
Q

What are the units for measuring energy

A

Joules

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11
Q

What happens when energy is dissipated

A

It spreads out and can’t be used for useful energy

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12
Q

When do most machines waste energy

A

When they get hot

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13
Q

Why do machines heat up

A

When 2 parts are moving against each other, friction causes them to heat up. The thermal energy in the machine is dissipated into the surroundings, and this is wasted energy

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14
Q

How can friction be reduced

A

By using a lubricant

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15
Q

What can be used as lubricant

A

Oil, other liquids and some gases

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16
Q

What is efficiency

A

A way of describing how good a machine is at transferring energy into useful forms

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17
Q

What is the efficiency between

A

0 and 1

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18
Q

When measuring efficiency, is it better to be nearer 0 or 1

A

1

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19
Q

What is the efficiency equation

A

(Useful energy transferred) divided by (total energy supplied)

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20
Q

What are the units of efficiency

A

There aren’t any

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21
Q

How do you increase the efficiency

A

Reduce the amount of wasted energy

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22
Q

How else can we increase efficiency

A

Find ways to make sure all the fuel going into the engine is being burned, or ways that thermal energy being wasted could be used

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23
Q

What does insulation do

A

Slow down the rate at which energy is transferred out of a house by heating.

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24
Q

What happens in conduction

A

Vibrations are passed on between particles in a solid

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25
Q

What are good thermal conductors

A

Metals

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26
Q

What are good thermal insulators

A

Wood and straw

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27
Q

What happens in convection

A

The part of a fluid that is warmer than the rest rises and sets up in a convection current

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28
Q

What is convection current

A

A current in a fluid

Think geography

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29
Q

What is the only way energy can be transferred through a vacuum

A

Radiation

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30
Q

What does it mean if a material has a low thermal conductivity?

A

It means that energy is not passed through them very easily by heating

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31
Q

What are materials that contain air good at?

A

They are good insulators because air has a very low thermal conductivity

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32
Q

What are the factors affecting the rate at which energy is transferred through a material by heating

A

Thickness, its thermal conductivity, and temp difference

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33
Q

How is the rate of energy transferred reduced

A

Increasing thickness, decreasing thermal conductivity and decreasing temp difference

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34
Q

What is GPE

A

Energy that is stored because of an objects position in a gravitational field

35
Q

Where does the object have to be to contain GPE

A

Above the surface of the earth

36
Q

What happens every time an object is moved upwards

A

It gains more GPE

37
Q

What does the amount of GPE stored depend on

A

The mass, the strength of gravity and how far up the object is

38
Q

What is the GPE equation

A

Change in GPE= mass x gravitational field strength x change in height

39
Q

What is earths gravitational field strength

A

10N/Kg

40
Q

Name an example of GPE in use

A

Birds dropping stones to break shells of nuts

41
Q

What does kinetic energy depend on

A

Mass and speed

42
Q

What’s the kinetic energy equation

A

Kinetic energy=1/2 x mass x speed squared

43
Q

Name a nuclear fuel

A

Uranium

44
Q

Why are nuclear fuels good to use as energy

A

They store a lot of energy in a small space

45
Q

What is nuclear fuel useful for

A

Spacecrafts as the mass of the fuel is important

46
Q

What are petrol and diesel made up from

A

Oil

47
Q

Name some non-renewable energy sources

A

Coal, oil, gas

48
Q

Why is petrol and diesel used in cars, planes and boats

A

Because it’s easy to store and use in engines, and has a lot of energy

49
Q

What is burnt to heat homes

A

Natural gas

50
Q

What does burning fossil fuels release

A

Carbon dioxide and other gases

51
Q

What do the carbon dioxide emissions contribute to

A

Climate change and global warming

52
Q

What causes further pollution problems

A

Emissions from power stations and vehicles

53
Q

What causes less pollution than burning coal

A

Burning natural gas

54
Q

What kind of power stations do not emit any emissions?

A

Nuclear power stations

55
Q

What’s the disadvantage of nuclear power stations

A

The waste they produce is radioactive and stays radioactive for millions of years

56
Q

What’s a difference between nuclear and fossil-fuelled power stations

A

Nuclear power stations are very expensive to dismantle at the end of their working life, and its expensive to get rid of the waste product safely

57
Q

What’s a big risk with nuclear power stations

A

If a major accident happens, the consequences are massive

58
Q

Name the different types of renewable energy

A

Hydro, solar, wind, geothermal and tidal

59
Q

What kind of energy do solar cells produce

A

Solar energy

60
Q

What do solar cells do

A

Convert solar energy straight into electrical energy in solar farms or on roof tops

61
Q

In what other ways can solar energy be used

A

In power stations or to heat water in homes

62
Q

What is a downfall of solar energy

A

It’s not available all the time

63
Q

How is hydroelectricity generated

A

By falling water into places where it can be trapped in high reservoirs

64
Q

What are some advantages of hydroelectricity

A

It’s available all the time, as long as the reservoirs don’t dry up and it can be started and stopped quickly unlike fossil fuel power stations

65
Q

When can wind energy be used

A

When the wind is not too fast or too slow

66
Q

What’s a disadvantage of wind turbines

A

People think they are ugly and can lower house prices if they are visible

67
Q

When can tide turbines generate electricity

A

When a huge barricade of turbines across a river estuary turn as the tide flows in and out

68
Q

When is tidal power available

A

At predictable times, but not all the time

69
Q

What’s a disadvantage of tidal turbines

A

They affect local wildlife and there are only a few places in the U.K that are suitable to have them

70
Q

bio-fuels be used as in the same way as what?

A

Fossil fuels

71
Q

What are bio fuels made from

A

Animal waste or plants

72
Q

What are bio fuels also made out of

A

Waste wood, parts of plants that aren’t eaten, and some crops are grown just to use as bio fuel

73
Q

What are bio fuels called

A

Carbon neutral

74
Q

Why are biofuels called carbon neutral

A

Because when they burn, they release the same amount of carbon dioxide as they took from when they were plants

75
Q

What do crops need to grow, be harvested and be made into biomass?

A

Energy, so really most biofuels aren’t carbon neutral

76
Q

What is geothermal energy

A

Electricity generated from heated rocks from under the ground

77
Q

Why can’t we only use renewables to generate electricity all the time?

A

Because they are unpredictable, and not available all the time

78
Q

Power equation

A

Work done divided by time taken

79
Q

What is the type of force that occurs when objects are touching

A

Contact forces

80
Q

Name some non contact forces

A

Gravity, magnetism,static electricity

81
Q

What is a force field

A

The space around an object where it can affect other objects

82
Q

Explain a Magnetic field

A

A field in which a magnet can attract objects made of magnetic materials such as iron

83
Q

Explain an electric field

A

A field in which two objects with the same charge produce a pair of forces that are equal in size and acting in different directions

84
Q

What is the resultant force

A

The total force that results from two or more forces acting upon an object

Physics (11 decks)

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