1. Energy

Question 1

What is the law of conservation of energy?

Answer 1

Energy is never used up, it is just transferred between different energy stores and objects. It can be transferred, stored or dissipated but can never be created or destroyed.

Question 2

What are the 8 energy stores?

Answer 2

• thermal
• kinetic
• gravitational potential
• elastic potential
• chemical
• magnetic
• electrostatic
• nuclear

Question 3

What are the 4 different ways energy can be transferred?

Answer 3

• mechanically (a force doing work)
• electrically (moving charges)
• heating
• radiation (by light or sound)

Question 4

What is a system?

Answer 4

A word for a single object or group or objects.

Question 5

What is a closed system?

Answer 5

A system where neither matter nor energy can leave. The net changer in the total energy of a closed system is always 0.

Question 6

How can energy be transferred by heating? (Example of kettle)

Answer 6

Energy is transferred electrically to the water which is the thermal energy store and causes the temp to rise.

Question 7

What is work done?

Answer 7

Another way of saying energy transferred.

Question 8

How can energy be transferred by doing work? (Example of a ball thrown)

Answer 8

As a person throws a ball upwards, work is done. This causes an energy transfer from the chemical energy store of the person to the kinetic energy store of the ball and arm.

Question 9

How can falling objects transfer energy? (Example of a ball with no air resistance)

Answer 9

The ball is accelerated by gravity so the gravitational force does work. As it falls, the gravitational potential energy store’s energy is transferred into kinetic energy.

Question 10

KE = 1/2 x m x v2 (what are the units?)

Answer 10

Ke= joules
Mass= kg
Speed= m/s

Question 11

GPE= mgh (what are the units)

Answer 11

GPE= joules
Mass= kg
Gravitational field strength= N/kg (usually 9.8)
Height= m

Question 12

EPE= 1/2 x k x e2 (what are the units?)

Answer 12

EPE= joules
Spring constant= N/m
Extension= m

Question 13

Power = energy transferred/ time (what are the units?)

Answer 13

Power= watts
Energy transferred= joules
Time= s

Question 14

What does lubrication do?

Answer 14

Reduces frictional forces that can save energy.

Question 15

What does insulation do?

Answer 15

Reduces thermal energy that is lost.

Question 16

How can you insulate a home?

Answer 16

• have thick walls made from a material with low thermal conductivity to reduce rate of energy transfer
• use thermal insulation such as
  
  • cavity walls (gap to reduce conduction)
  • loft insulation (insulator)
  • double glazed windows (gap to reduce conduction)
  • draught excluders (reducers convection)

Question 17

What happens to all wasted/ dissipated energy?

Answer 17

It is eventually transferred to thermal energy stores

Question 18

What are non- renewable energy resources?

Answer 18

Energy resources that will run out one day.

Question 19

What are some examples of non- renewable energy stores?

Answer 19

• coal
• oil
• natural gas

Question 20

What 3 things do coal, oil and natural gas have in common?

Answer 20

• they will all run out one day
• they all do damage to the environment
• they are reliable

Question 21

What are renewable energy resources?

Answer 21

Energy resources that will never run out.

Question 22

What are 7 examples of renewable energy resources?

Answer 22

• solar energy
• wind
• water waves
• hydro electricity
• bio fuel
• tides
• geothermal

Question 23

What do all renewable energy resources have in common?

Answer 23

• they will never run out
• most of them do damage to the environment but in less harmful ways to the environment
• they don’t provide much energy and some are unreliable

Question 24

What are the advantages of wind turbines?

Answer 24

• there’s no pollution
• no fuel costs and minimal running costs
• no permanent landscape damage

Question 25

What are the disadvantages of wind turbines?

Answer 25

- they spoil the view (need 1500 to replace one coal fired power station) - they can be very noisy - stop when the wind stops and it is impossible to increase supply in strong winds - high initial costs

Question 26

What are the advantages of solar cells?

Answer 26

- best for calculator and watch batteries - often used in remote places - no pollution - energy is free and running costs are super low

Question 27

What are the disadvantages of solar cells?

Answer 27

- lots of energy to manufacture - reliable only in daytime - can’t increase power output when needed - high initial costs - small scale

Question 28

What are the advantages of geothermal power?

Answer 28

- free and reliable - can be used to generate electricity or heat buildings directly

Question 29

What are the disadvantages of geothermal power?

Answer 29

- only possible in volcanic areas with hot rocks at the surface - high cost for the amount of energy - less locations

Question 30

What are the advantages of hydro electric power?

Answer 30

- no pollution - less human disadvantages - immediate response - high reliability - no fuel costs and minimal running costs

Question 31

What are the disadvantages of hydro electric power?

Answer 31

- usually requires flooding of a valley by building a big dam - huge impact on environment (flooding, habitat loss, unsightly views) - high initial costs - works on only a small scale - works only in remote areas

Question 32

What are the advantages of wave power?

Answer 32

- no pollution - no fuel costs and minimal running costs - useful on small islands

Question 33

What are the disadvantages of wave power?

Answer 33

- need lots of small wave powered turbines around the coast - disturbs seabed and habitats - spoils view - hazard to boats - fairly unreliable - high initial costs - not useful on large scale

Question 34

What are the advantages of tidal barrages?

Answer 34

- no pollution - reliable - no fuel costs and minimal running costs - can generate a significant amount of energy

Question 35

What are the disadvantages of tidal barrages?

Answer 35

- prevents access by boats - spoils view - alters habitat - height of tides can change energy produced - high initial costs - only some suitable estuaries

Question 36

What are the advantages of bio fuels?

Answer 36

- they are carbon neutral mostly - fairly reliable (crops take short time to grow)

Question 37

What are the disadvantages of bio fuels?

Answer 37

- cannot respond to immediate energy demands - cost is very high - not enough space or water for growing crops to eat - large areas of forest have been cleared resulting in loss of habitats - forests have been cleared using slash and burn method

Question 38

How does wind power work?

Answer 38

Each turbine has a generator inside and the rotating blades turn the generator and produce electricity

Question 39

How do solar cells work?

Answer 39

Solar cells generate electric currents directly from sunlight

Question 40

How does geothermal power work?

Answer 40

Energy is taken from underground thermal energy stores

Question 41

How does hydro electric power work?

Answer 41

It transfers energy from the kinetic store of falling water by creating dams

Question 42

How does wave power work?

Answer 42

Turbines spin due to water flow and energy is sent to a generator

Question 43

How do tidal barrages work?

Answer 43

Big dams are built with turbines in them. As the tide comes in it fills up the estuary and the tide is allowed out at a control speed. (Energy from kinetic energy)

Question 44

How does bio fuel work?

Answer 44

Either plant products or animal dung are burnt to produce thermal energy.

Question 45

What environmental problems are created by non renewable energy sources?

Answer 45

- greenhouse effect - sulfur dioxide released from burning coal and oil which causes acid rain - spoils views - oil spillages kill mammals and birds - nuclear waste is dangerous and difficult to dispose of - nitrogen oxide can cause acid rain and smog