P1.4 Generating electricity

Question 1

Name some non-renewable resources (4)

Answer 1

• Coal
• Crude oil
• Natural gas (methane)
• Nuclear fuels (uranium and plutonium)

Question 2

Name some renewable resources (7)

Answer 2

• Biofuels
• Geothermal
• Hydroelectricity
• Solar radiation
• Tidal changes
• Wave action
• Wind turbines

Question 3

What is a positive and negative impact of renewable and non-renewable resources?

Answer 3

Renewable

• Won’t run out
• Only a small amount of energy produced

Non-renewable

• Bad for the environment
• Creates a lot of energy

Question 4

Describe the process in a power station

Answer 4

1) Coal is crushed and heated (chemical energy = thermal energy)
2) Water boils an evaporates
3) Steam turns the turbines (thermal energy = kinetic energy)
4) Energy goes to generator making magnets turn (Kinetic energy = electrical energy)

Question 5

What is biofuel?

Answer 5

Organic material (dung, sugar canes, dead plants and animals) that is used as fuel

Question 6

How can we use biofuel?

Answer 6

Burn biofuel instead of coal to produce water vapour

Question 7

What is good about Biofuel?

Answer 7

It is carbon neutral

Question 8

What does carbon neutral mean?

Answer 8

The same amount of carbon dioxide is released into the atmosphere as the plant took in so there is no difference in the carbon dioxide levels when biofuel is burnt

Question 9

Describe the process of using wind power

Answer 9

1) Wind s produced by convection currents in the Earth’s atmosphere
2) The wind causes the turbines to move (kinetic energy)
3) The blades turn which are connected to the gears
4) The generator creates electrical energy

Question 10

What are the advantages of using wind power? (3)

Answer 10

• Renewable
• No fuel costs
• No harmful gases are produced

Question 11

What are the disadvantages of using wind power? (3)

Answer 11

• Noisy (sound energy wasted)
• Spoil view of landscape
• Amount of energy depends on strength of wind

Question 12

Describe the process of using wave power/water power?

Answer 12

1) A tidal barrage contains electricity generators
2) As the water passes through it, it turns the magnets in them creating electricity
(Gravitational potential energy at the top of the dam)

Question 13

What are the advantages of using wave power? (5)

Answer 13

• Renewable
• No harmful gases produced
• No fuel costs
• Very reliable (water always running)
• Can be switched on easily

Question 14

What are the disadvantages of using wave power? (4)

Answer 14

• Hard to create a lot of energy
• Destroys habitats
• Can flood farmland (push people from their homes)
• Rotting vegetation under water can produce methane a greenhouse gas

Question 15

Describe the process of solar panels

Answer 15

1) The panel takes in thermal energy from the sun
2) The heat turns the water in the tank to steam
3) The water is pumped giving it more gravitational potential energy
4) The steam is piped to ground level where it turns the generator creating electricity

Question 16

What are the energy transfers in a solar panel?

Answer 16

Thermal energy - Kinetic energy - gravitational potential

energy - electrical energy

Question 17

Describe the process of the national grid

Answer 17

1) The generator produces electricity
2) The step-up transformer increase the voltage so less current is needed to transfer the same amount of power
3) It travels to the pylon
4) The step-down transformer decreases the voltage so it is safe to use in the house

Question 18

What are the voltages after the generator, step-up transformer and step-down transformer?

Answer 18

Generator = 25000 V
Step-up transformer = 32000 V
Step-down transformer = 240 V

Question 19

What are the advantages and disadvantages of underground cables?

Answer 19

Advantages
- Safe

Disadvantages

• Hard to maintain
• Costs a lot

Question 20

What are the advantages and disadvantages of overhead cables?

Answer 20

Advantages

• Easy to maintain
• Costs less

Disadvantages

• Not very safe
• Ugly