Energy Transfers

Question 1

Kinetic energy

Answer 1

Anything moving has energy in its kinetic energy store

Question 2

Thermal energy

Answer 2

Any object - the hotter it is, the more energy it has in its store

Question 3

Chemical

Answer 3

Anything that can release energy by a chemical reaction

Eg: foods, fuels

Question 4

Gravitational potential

Answer 4

Anything in a gravitational field

Question 5

Elastic potential

Answer 5

Anything stretched like springs and rubber bands

Question 6

Electrostatic

Answer 6

Eg: two charges that attract or repel each other

Question 7

Magnetic

Answer 7

Eg: two magnets that attract or repel each other

Question 8

Nuclear

Answer 8

Atomic nuclei release energy from this store in nuclear reactions

Question 9

Mechanically transferred

Answer 9

An object moving due to a force acting on it

Eg: pushing, pulling, stretching or squashing

Question 10

Electrically transferred

Answer 10

A charge moving through a potential difference

Eg: charges moving round a circuit

Question 11

By heating

Answer 11

Energy transferred from a hotter object to a colder object

Eg: heating a pan of water on a hob

Question 12

By radiation

Answer 12

Energy transferred
Eg: by light/sound waves
Eg: energy from the sun reaching earth as light

Question 13

What is the principle of conservation of energy?

Answer 13

Energy can be stored, transferred between stores, and dissipated - but it can never be created or destroyed

The total energy of a closed system has no net change

Question 14

What is the equation used to calculate efficiency?

Answer 14

Efficiency = useful energy output / total energy output x 100%

Question 15

Describe energy transfers of a ball rolling up a slope

Answer 15

1) Transferred MECHANICALLY from the KINETIC energy store of the ball to its GRAV POT energy store.
2) some energy transferred MECHANICALLY to its THERMAL energy stores of ball and the slope due to friction, then by heating to THERMAL energy stores of surroundings - energy is wasted

Question 16

Describe energy transfers a bat hitting a ball

Answer 16

1) some energy is usefully transferred MECHANICALLY from the kinetic energy store of bat to kinetic energy store of ball.
2) Rest of energy is wasted. Some energy in kinetic energy store of bat is transferred MECHANICALLY to the thermal energy stores of bat, ball and surroundings.
3) remaining energy carried away by sound.

Question 17

Describe energy transfers of an electric kettle boiling water

Answer 17

1) energy transferred electrically from mains to the thermal energy store of kettles heating element.
2) it is then transferred by heating to thermal energy store of water.
3) some energy is wasted and transferred by heating from thermal energy stores of heating element and water to the thermal energy stores of surroundings.

Question 18

Battery powered toy cars

Answer 18

1) energy usefully transferred electrically from the chemical energy store of batter to kinetic energy store of car and carried away by light from headlights.
2) wasteful energy transfers occur, to thermal energy stores of car and surroundings and waste fully carried away by sound

Question 19

Energy transfers in fossil fuels

Answer 19

1) As the fossil fuel burn, it transfers energy by heating and stored in the thermal energy store of water and steam.
2) Then, the energy is transferred mechanically to the turbine.
3) The energy is transferred mechanically to the generator, and then transferred as electricity.

Question 20

Advantages of fossil fuels

Answer 20

1) readily available and provide reliable source of power
2) gas fired power stations can be turned on and off at short notice, thereby allowing electricity companies to respond to changes in demand throughout the day

Question 21

Disadvantages to fossil fuels

Answer 21

1) non-renewable and produce gases which contribute to global warming and cause pollution.
2) we have limited reserves of all the fossil fuels

Question 22

Energy transfers in nuclear power

Answer 22

During the process, energy is transferred from nuclear energy stores to thermal energy stores by heating, then mechanically to kinetic energy stores, and finally transferred electrically through the national grid

Question 23

Advantages of nuclear power

Answer 23

1) plenty of nuclear fuel so resources will last for a long time
2) great amount of energy released for each kg of nuclear fuel
3) does not produce gases which contribute to global warming

Question 24

Disadvantages of nuclear power

Answer 24

1) produce radioactive waste which has a long half-life
2) waste needs to be stored safely for many years
3) expensive to produce

Question 25

Energy transfers in wind power

Answer 25

Wind turbines use energy from the kinetic energy store of moving air to generate electricity. Wind turns blades, which turn a generator inside it.

Question 26

Advantages of wind power

Answer 26

Wind power is clean and has no waste products Renewable

Question 27

Disadvantages of wind power

Answer 27

Unreliable - if wind is too light no power is generated If wind too strong turbines can overheat Make a noise that disturbs people living close to them

Question 28

Energy transfers in tidal barrages

Answer 28

The energy is transferred from the kinetic energy stores of the water to the kinetic energy store of the turbine, and used to generate electricity.

Question 29

Advantages of water power

Answer 29

Reliable and have no waste products Hydroelectric power is reliable because rivers usually flow Water is free and does not need mining or transporting

Question 30

Disadvantages of water power

Answer 30

- initial costs are high | - environmental issues

Question 31

Energy transfers in geothermal power

Answer 31

Water is pumped in pipes down to hot rocks and forced back up due to pressure to turn a turbine which drives a generator. So the energy is transferred from thermal energy stores to kinetic energy stores and are used to generate electricity

Question 32

Advantages of geothermal power

Answer 32

Renewable and reliable Cheap No waste products

Question 33

Disadvantages of geothermal power

Answer 33

Only available in some regions of geological activity like Iceland.

Question 34

Energy transfers in solar heating systems

Answer 34

Radiation from sun transfers to the thermal energy store of water. Water is pumped through pipes, which are placed on the roof of a house. In this way the water is warmed.

Question 35

Advantages of solar power

Answer 35

Once panels are installed solar power is free at source Require little maintenance Good long term investment Renewable No waste products

Question 36

Disadvantages of solar power

Answer 36

Initial high investment Unreliable due to weather Cannot operate at night and less effective in winter

Question 37

Energy transfers from n hydroelectricity

Answer 37

Rainwater is caught and allowed out through turbines, transferring energy from the gravitational potential energy store of the water to kinetic energy stores as it falls, which is used to generate electricity