1.      F/H

When  different  parts of a substance are at different temperatures, _________  is transferred by the substance from places where the temperature is _______ to places where the temperature is _______.

heat (energy), higher, lower

2.      F/H

Transfer of energy by a substance, without the substance itself moving, is called __________.

conduction

3.      F/H

what kind of materials are good conductors of heat?

metals

4.      F/H

What kind of materials ar poor conductors of heat?

Non-metals are usually poor conductors (insulators). Gases are very poor conductors.

5.      F/H

Liquids and gases can flow and so can carry energy from places where the temperature is ________ to places where the temperature is _________.  This process is called __________

higher, lower, convection

6.      F/H

What materials transfer heat energy best by convection?

liquids or gases

7.      F/H

What is method in which heat energy can be transferred through empty space?

radiation

8.      F/H

Thermos or vacuum flasks aim to keep foods at a constant temp.  Describe how they reduce heat transfer by: (a) conduction.

(a) the flask is a double skin with a vacuum in between

9.      F/H

(b) convection

(b) has a thick plastic lid on top

10. F/H

(c) radiation

(c)  flask has a mirrored surface.

11. F/H

The ________ an object is, the more energy it radiates.

hotter

12. F/H

Dark, matt surfaces emit less/more radiation than light, shiny surfaces at the same temperature.

more

13. F/H

Dark, matt surfaces are poor/good absorbers of radiation.  The are poor/good reflectors of radiation.

good, poor

14. F/H

Light, shiny surfaces are poor/good reflectors (poor/good absorbers) of radiation.

good, poor

15. F/H

describe four ways that a house can loose heat energy

through windows, through the roof, through the floor, through the walls, draughts around doors

16. F/H

descibe (and explain) ways in which the rates of these energy transfers can be reduced.

double glazing (double layer of glass with air gap - reduces conduction/convection through glass), loft insulation (fibre glass, trapped air is a poor conductor), carpeting (trapped air), cavity wall foam (double wall with air gap filled with trapped air), fluffy snake :-)

17. H

It costs money to insulate a home.  E.g. Double glazing costs £2000 and saves £100 a year on your fuel bills, draught excluders cost £5 and save £30 a year on your fuel bill - which is the most cost effective?

draught excluders - pay for themselves in months - whereas double glazing takes 20 years to pay for itself

18. H

Explain why conduction occurs in metals.

because the hotter the metal is the more kinetic energy its free electrons have and the faster they diffuse through the metal. The more vigorous movement of the electrons in the hot region of the metal is also transferred, via collisions, to adjacent electrons which, in turn, transfer energy to the electrons adjacent to them, and so on.

19. H

Explain why convection occurs in liquids and gases

because their particles move faster when they are hot causing the liquid or gas to expand. Warm regions are then less dense than cold regions. The warm regions rise up through the colder regions and colder regions replace the warmer regions.

20. H

What is the process that thermal radiation uses to transfer heat?

Thermal radiation is the transfer of energy by waves.

21. H

describe the particles of matter involved in the transfer of heat by thermal radiation

trick question: Particles of matter are not involved

22. F/H

Describe the energy changes in an electric light bulb.  Which are the useful and non-useful energy changes?

electricity --> light (useful) and heat (non-useful)

23. F/H

Most energy changes involve non-useful energy being wasted as ______

heat

24. F/H

The energy which is 'wasted' during energy transfers and the energy which is usefully transferred both end up being transferred to the surroundings which become __________

warmer

25. F/H

If energy cannot be created or destroyed, why do we say that the heat given out by non-useful changes is "wasted"?

The energy becomes increasingly spread out and becomes increasingly more difficult to use for further useful energy transfers.

26. F/H

What is the EFFICIENCY of a device?

The fraction of the energy supplied to a device which is usefully transferred

27. F/H

How do energy efficient light bulbs get their name?

They waste less energy as heat.

28. H

Calculate the efficiency of a "green" light bulb that produces 50J of light for every 120J of electricity transferred?

efff = useful energy / energy input x 100% = 50/120 x 100 = 41.7%

29. H

Calculate the efficiency of a filament light bulb that produces 50J of light for every 1200J of electricity transferred?

eff = 50/1200 x 100% = 4.17%

30. H

Why is the "green" light bulb "green"?

possibly because it wastes less energy - could also be because it lasts longer so less wasted in manufacturing

31. F

Coal, oil, gas and wood are all fuels.  Why?

They release energy when they are burned.

32. F

Name 4 non-renewable fuels

coal, oil and gas and nuclear fuels

33. F

Why "non-renewable"?

Once they are used up they cannot be replaced.

34. F

name 3 fossil fuels

coal, oil and gas

35. F

Why "fossil"?

Been in the earth for millions of years

36. F

Why is wood a renewable energy resource?

More trees can be grown to replace trees that are cut down to provide wood for fuel.

37. F/H

Name 5 more renewable energy resources

sunlight, the wind, the waves, running water and the tides.

38. F/H

Why "renewable"?

These energy resources will not run out.

39. F/H

Electricity is a very convenient and widely used energy source. It is generated in ____  ____ using some other energy resource.

power stations

40. F/H

In most ______ _____, energy from fuel is used to heat _______. In Britain, many power stations burn ______ fuels. Other power stations use ________ fuel, mainly _________ and plutonium. The steam which is produced is used to drive ________. These then drive _______ which produce electricity.

power stations, water, fossil, nuclear, uranium, turbines, generators

41. F/H

Electricity can also be generated from renewable energy resources.  Energy from renewable resource can be used to drive _______ directly. The resources used in this way include …

turbines, wind, waves, flow of water, steam from hot rocks, the sun's energy

42. F/H

The steam needed to drive ________ can be produced by pumping water through hot _____ below the surface of the Earth. The energy which makes the ______ hot is constantly being released by _________ elements, including uranium, as they _______. This happens much more slowly/quickly than in a nuclear reactor.

turbines, rocks, rocks, radioactive, decay, slowly

43. F/H

Electricity can be produced directly from the Sun's radiation using _____ ______

solar cells

44. F/H

describe an environmental problem caused by generating electricity using:

(a) coal

acid rain caused by S -->  S02, subsidence caused by collapsing mines

45. F/H

(b) oil

green house effect caused by carbon dioxide build up in the atmosphere, acid rain caused by S and N oxides

46.  

(c) nuclear

waste remains radioactive for thousands of years - hazards associated with leaks

47.  

(d) large-scale wind farms

noise pollution, thought to be a threat to tourism, destruction of wildlife habitats

48. F/H

(e) large scale tidal schemes

threat to wildlife habitats, flooding of natural coastal plains

49. F/H

(f) hydroelectric shemes

again threat to habitats, flooding of river valleys when creating dams

50. F/H

Which of the resources above cannot be quickly started in times of peak demand

coal fired power stations take time to reach operating temp - they tend not the be switched off

51. H

Discuss some of the financial constraints of using renewable energy resources

though there are no fuel costs with renewables, the energy is dilute so that the capital cost of the generating equipment is high

52. H

Discuss some of the financial constraints of using nuclear as an energy source

the fuel costs for nuclear power stations are low, the cost of building the power stations, and of de-commissioning them at the end of their useful life, is high

53. F/H

Energy is measured in ________

joules

54. F/H

When a force moves an object, energy is transferred and _____ is done

work

55. F/H

What formula connects work done, force and distance?

Work done = Force x distance

56. F/H

What work is done by a lift lifting a force of 5000N up to a height of 20m?

wd = F x d = 5000 x 20 = 10000J

57. F/H

What energy is released by a falling load of waste (of mass 5kg) released by an plane from a height of 30000m.  I know I know - happens all the time :-)

use work done formula remembering that (a) work done = energy and (b) 5kg = 50N.  Wd = F x d = 50 x 30000 = 1500000J.  Aren't Physics teachers sad?

58. F/H

What is "power"

How "fast" energy is transferred

59. F/H

The greater the power, the less/more energy is transferred in a given time.

more

60. F/H

Using power = work done / time taken calculate the energy given out by a 2kW heater used for 2 minutes

p=work/t OR work (energy) = power x time = 2000W x 120 seconds = 240000J

61. F/H

what do we call the energy stored in an object because of the height to which the object has been lifted against the force of gravity.

gravitational potential energy?

62. F/H

describe the energy changes of a falling object

grav pot energy --> kinetic energy

63. F/H

On Earth the gravitational field strength is about ____ N/kg.

10

64. F/H

Using weight = mass x grav. Field strength, what is the wieght of a 500gramme book?

weight = mass (in kg) x 10 = 0.5 x 10 = 5N

65. F/H

what is the mass of a 500N object?

500 / 10 = 50kg

66. F/H

_____ _______ _______is the energy stored in an elastic object when work is done on the object to change its shape

elastic potential energy

67. F/H

what is kinetic energy?

the energy an object has because of its movement.

68. F/H

An object has greater kinetic energy the greater its ____ and the greater its ____

mass, speed

69. F/H

use KE=1/2 mv² to calculate the kinetic enrgy of a 50kg boy running at 10m/s

KE= 1/2 x 50 x 102 = 2500J