Energy Resources and Energy Transfer

Question 1

Describe how air moves near the coast on a warm day

Answer 1

1) energy transferred from sun
2) air over land is heated
3) warmer air over land expands
4) air becomes less dense
5) therefore rises
6) cooler air over sea becomes denser
7) cooler air over sea sinks
8) air from over the sea moves inland to replace rising air

Question 2

Why is air a bad conductor?

Answer 2

Air particles are widely spaced

Question 3

How do generators create electricity?

Answer 3

Turn magnets inside a coil

Question 4

What is thermal energy?

Answer 4

Energy possessed by hot objects

Question 5

What is light energy?

Answer 5

Energy emitted by luminous objects

Question 6

What is electrical energy?

Answer 6

Energy carried around circuits by charged particles

Question 7

What is sound energy?

Answer 7

Energy from vibrating object

Question 8

What is kinetic energy?

Answer 8

Energy possessed by moving objects

Question 9

What is chemical energy?

Answer 9

Energy contained in bonds between atoms

Question 10

What is nuclear energy?

Answer 10

Energy contained inside atomic nuclei

Question 11

What is elastic potential energy?

Answer 11

Energy possessed by stretched or squashed objects

Question 12

What is gravitational potential energy?

Answer 12

Energy possessed by an object that has been lifted up in a gravitational field

Question 13

What is the principle of conservation of energy?

Answer 13

Energy can neither be creates nor destroyed: it can only be transferred from one state to another

Question 14

What is conduction?

Answer 14

The transfer of thermal energy through a substance without the substance moving

Question 15

Describe the process of conduction

Answer 15

1) as substance is heated the particles begin to vibrate more vigorously
2) they then transfer their energy to neighbouring particles via collisions
3) these particles then vibrate more vigorously

Question 16

Why are metals good conductors?

Answer 16

They have free electrons that can move easily and speed up the transfer of energy

Question 17

What is convection?

Answer 17

The transfer of heat energy through fluids by the upward movement of warmer less dense regions of air

Question 18

Describe the process of convection

Answer 18

1) heated air expands
2) hot air becomes less dense
3) hot less dense air rises
4) cooler air replaces it
5) as air moves away from heat source air cools and becomes more dense
6) cool air falls
7) convection current is continuous

Question 19

What is radiation?

Answer 19

The transfer of energy by infra-red radiation

Question 20

What is the best emitter + absorber of radiation?

Answer 20

Matt black surface

Question 21

What reduces heat loss by conduction?

Answer 21

1) cavity walls
2) double glazing
3) loft insulation
(ALL trap air which is a poor conductor)

Question 22

What reduces heat loss by convection?

Answer 22

1) loft insulation

2) draught excluders

Question 23

What reduces heat loss by radiation?

Answer 23

Line walls behind radiators with reflective foils

Question 24

How does evaporation cool water?

Answer 24

1) temperature is proportional to the average kinetic energy of the particles
2) particles leave the surface of the water
3) highest energy particles leave the liquid
4) average kinetic energy of remaining particles in the liquid is reduced

Question 25

what are the advantages of using wind turbines instead of coal-fired power stations?

Answer 25

1) reduced running costs
2) no atmospheric pollution (no CO2 emissions)
3) renewable resource

Question 26

why have wind turbines not replaced coal fired power stations completely?

Answer 26

1) Wind turbines are less reliable as the wind does not always blow at the right speed
2) Wind turbines spoil the view and are noisy
3) Wind turbines require a large, windy site
4) Wind turbines are difficult to maintain as they usually need to work in a remote location
5) One turbine produces less power than a power station
6) Building a wind farm is very expensive

Question 27

what is meant by the term non-renewable?

Answer 27

energy source which cannot be replaced

Question 28

explain how the electrical energy from a remote wind farm is transmitted to large cities

Answer 28

1) Step-up transformer used at the wind farm
2) voltage increased for transmission
3) transmitted at high voltage and low current
4) little energy is wasted during transmission
5) Step down transformer at ‘other end’
6) voltage reduced to 230V/for safety/for homes

Question 29

what is the mains voltage?

Answer 29

230V

Question 30

Some power stations use uranium as a fuel. Describe the problems that arise from the disposal of waste from this type of power station.

Answer 30

1) Radioactive
2) High activity
3) Long half live means need for long term storage
4) Danger/harm to people
5) Expensive to contain/dispose of
6) Need for security/shielding

Question 31

explain why it is harder to give objects an electrostatic charge when air is humid

Answer 31

water is a conductor so electrons move from objects