everything Flashcards

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0
Q

Do all objects give off infrared radiation?

A

All objects emit infrared radiation.

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1
Q

What is infrared radiation?

A

Infrared radiation is energy transfer by magnetic waves.

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2
Q

How does infrared radiation depend on the temperature of an object?

A

The hotter an object is, the more infrared radiation it emits over a given time.

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3
Q

Which surfaces are the best emitters of infrared radiation?

A

Dark Matt surfaces emit more infrared radiation than light, shiny surfaces.

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4
Q

Which surfaces are the best absorbers of infared radiation?

A

Dark, Matt surfaces absorb more infrared radiation that light shiny surfaces.

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5
Q

What surfaces are the best reflectors of infrared radiation?

A

Light, shiny surfaces reflect more infrared radiation than dark Matt surfaces.

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6
Q

How are solids, liquids and gases different?

A

Flow, shape and density are the properties used to describe each state of matter.

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7
Q

How are particles in a solid arranged and describe it’s shape?

A

The particles in a solid are held in fixed positions and they vibrate their fixed positions so that the solid keeps it’s shape. the particles in a gas move about randomly and are much further apart than in a solid or a liquid.

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8
Q

What materials make the best conductors?

A

Metals are the best conductors of energy because they contain free electrons.

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9
Q

What materials make the best insulators?

A

Materials such as wood and plastic ( in general non metals )

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10
Q

What are the three states of matter?

A

Solid, liquids and gases.

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11
Q

What happens to the particles when the temperate of a substance increases?

A

The particles move faster.

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12
Q

How are the particles arranged in a liquid and describe it’s shape?

A

the particles in a liquid move about at random and are in contact with each other, because they move about at random they don’t have their own shape and it can flow.

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13
Q

How are the particles in a gas arranged and describe it’s shape?

A

The particles in a gas move about at random much faster and on average much further apart from eachother than in a liquid. The density of a gas is thus much less than that of a solid or a liquid.

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14
Q

In general what is the energy levels in: solids, liquids gases.

A

Gas < liquid

Liquid < solid

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15
Q

Why do metals make such good conductors?

A

Metals contain lots of free electrons which move about at random inside the metal and collide with eachother and with the positive ions ( ions are charged particles) When a metal did is heated at one end the free electrons at the hot end gain kinetic energy and move faster.

These electrons diffuse ( spread out ) and collide with other free electrons and ions in the cooler parts of the metal, as a result they transfer kinetic energy to these electrons and ions. So energy is transferred from the hotter end to the cooler end.

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16
Q

Why are non metals bad conductors compared with metals?

A

In non metals all the electrons are held in the atoms and energy transfer only games place because the atoms vibrate and shake eachother. This is much less effective than energy transfer by free electrons thus making them worse conductors.

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17
Q

What is convection and why does it happen?

A

Convection is the circulation of a fluid ( liquid of gas ) cauSed by heating it.
Heating a liquid or a gas makes it less sense so it then rises and then when t cools down it falls (because when it cools it becomes more dense ). Causing a convection current from the hotter parts to the cooler parts.

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18
Q

What is evaporation?

A

Evaporation is when a liquid turns into a gas.

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19
Q

What is condensation?

A

Condensation is when a gas turns into a liquid.

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20
Q

How can the rate at which evaporation occurs be increased?

A

By:

  • increasing the surface area of the liquid
  • increasing the liquids temperature
  • creating a draught of air across the liquids surface
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21
Q

What factors increase the rate at which condensation occurs?

A
  • increasing the area of the surface

- reducing the temperature of the surface.

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22
Q

What affects the rate at which an object transfers energy?

A

The surface area and volume
What the objects made from
The nature of the surface which the object is in contact with

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23
Q

How can the rate at which energy is transferred be increased?

A

The bigger the temperature difference between an object and it’s surroundings the faster the rate at which energy is transferred by heating.

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24
Q

What does U-values measure?

A

How affective of an insulator a material is because it tells us how much energy per second passes through different materials.

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25
Q

What does a low U-value tell us?

A

That it is a better insulator than a higher U-value.

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26
Q

What is the specific heat capacity of a substance?

A

The amount of energy required to change the temperature of one migrants of the substance by 1 degrees Celsius.

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27
Q

What does the term ‘ pay back time ‘ mean?

A

The amount of time it takes to get back your investment.

28
Q

why is knowing the efficiency of an appliance important?

A

So that we can choose between then and get the most cost affective.

29
Q

Can energy be destroyed or created?

A

No it can only be transferred usefully, stored or dissipated ( spreads out).

30
Q

What is wasted energy?

A

Energy that is not useful energy.

31
Q

What eventually happens to waste energy?

A

It transfers into the surroundings which become warmer and the wasted energy becomes increasingly spread out and so becomes less useful.

32
Q

What is an example of an every day appliance that uses an energy transfer?

A
  • light bulb
  • kettle
  • hair drier
33
Q

What affects the amount of energy transferred by an appliance?

A

The amount of time it is switched on and is power.

34
Q

What does the national grid do?

A

It distributes electricity.

35
Q

How is electricity generated in a power station?

A

An energy source is used to hear water and the steam produced drives a turbine that is coupled to an electrical generator.

36
Q

What three fossil fuels are burned in power stations?

A

Coal oil and natural gas.

37
Q

What nuclear fuels are used in a nuclear power station and why do we use them?

A

Uranium and plutonium are used as the fuel in a nuclear power station, much more energy is released per kg from uranium or plutonium than from fossil fuel.

38
Q

What other fuels can be used to generate electricity that is renewable?

A

Biofuels are renewable sources of energy such as methane and ethanol.

39
Q

What type of power station uses water running downhill to generate electricity?

A

Hydroelectricity generators are turned by water running down hill.

40
Q

How do we use tides to generate electricity?

A

A tidal power station traps each high tide and uses it to turn electricity.

41
Q

How do we use waves to generate electricity?

A

They turn a floating generator.

42
Q

What is geothermal energy?

A

It comes from the energy released by radioactive substances deep inside the earth.

In some volcanic areas hot water and steam rise to the surface and the steam can be tapped and used to drive turbines ( geothermal energy )

43
Q

How can small scale production of electricity be useful in certain areas?

A

Hydroelectricity could be used in remote areas.

Solar panels could be used for road signs.

44
Q

What different factors affect the environment caused by using different energy resources?

A
  • the release of substances in the atmosphere.
  • The production of waste materials
  • noise and visual pollution
  • the destruction of wildlife habitats.
45
Q

What is the national grid?

A

A network of cables and transformed that distributes electricity To our homes from power stations and renewable energy generators.

46
Q

Why do we use a high voltage in the national grid?

A

Increasing the voltage reduces the current required and this reduces the energy loss within the cables.

47
Q

What are step-up and step-down transformers used for within the national grid?

A

Step-up: used to step up the power station voltages to the grid voltage.

Step down: used to step the grid voltage down so that we can use it in our homes.

48
Q

can electromagnetic waves travel through a vacuum?

A

They can and they do so at the same speed

49
Q

What type of energy is transferred by longitudinal waves?

A

Sound and some mechanical waves

50
Q

Can longitudes leaves travel through a vacuum?

A

No

51
Q

What do waves do?

A

They transfer energy

52
Q

What are type of wave are electromagnetic waves?

A

Transverse waves

53
Q

What do longitudinal waves show?

A

Areas of compression and refraction

54
Q

Can electromagnetic waves travel through space?

A

Yes, they can travel through space despite it being a vacuum and at the same speed.

55
Q

Give 2 examples of radio waves?

A

Television

Radio

56
Q

Give two examples of microwaves?

A

Mobile phones

Satellite television

57
Q

Give an example of where infrared is used?

A

Remote controls

58
Q

Give an example of what visible light is used for?

A

Photography

59
Q

What does frequency mean?

A

The number of wave crests passing a point every second.

Pitch

60
Q

What does wavelength mean?

A

The distance from one wave crest to another wave crest ( the length of a wave )

61
Q

What is the amplitude?

A

Loudness

62
Q

What is the normal?

A

A construction line perpendicular to the reflecting surface at the point of incidence.

63
Q

What’s the angle if incidence?

A

Equal to the angle of reflection

64
Q

What is the image produced in a plane mirror?

A

A virtual image is produced

65
Q

What are sound waves?

A

Longitudes waves which cause vibrations in the medium which are detected as a sound

66
Q

How is the pitch of a sound is determined?

A

By it’s frequency and it’s amplitude

67
Q

What are echos?

A

Echos are reflections or sounds.