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Question 1

1. Why is electricity convenient?

Answer 1

• it is easily transmitted over distances

- it can be used in many ways

Question 2

2. How is mains electricity produced?

Answer 2

• by generators
• generators use electromagnetic induction to turn kinetic energy from the turbines in power stations into mains electricity

Question 3

3. How do generators produce a voltage?

Answer 3

Generators produce a voltage across a coil of wire by spinning a magnet near it

• magnet rotates in a coil of wire
• as magnet turns, magnetic field through the coil changes
• change in magnetic field induces voltage= current flows in coil

Question 4

4. What is the relationship between the size of the current supplied by a generator and the amount of primary fuel it uses every second? Why?

Answer 4

• the bigger the current supplied by a generator, the more primary fuel it uses every second
• this is because you have to turn the magnet faster

Question 5

5. What is a primary energy source? What is an example?

Answer 5

• what is being used to power the turbine

- e.g. coal

Question 6

5. What happens in thermal power stations?

Answer 6

-primary energy is used to heat water; the steam produced drives a turbine which is coupled to an electrical generator that converts the movement of the turbine (kinetic energy) into electricity

Question 7

6. What are the basic components of a thermal power station?

Answer 7

Furnace → boiler → turbine → generator → step up transformer → National Grid

Question 8

6. What are the basic components of a nuclear power station?

Answer 8

Reactor → boiler → turbine → generator → step up transformer → National Grid

Question 9

6. What are the basic components of a hydroelectric power station?

Answer 9

Turbine → generator → step up transformer → National Grid

Question 10

6. What happens in the furnace in a thermal power station?

Answer 10

• combustion

- chemical → thermal energy

Question 11

6. What happens in the boiler in a thermal power station?

Answer 11

• water boiled to steam and funnelled down pipes

- thermal → kinetic energy

Question 12

6. What happens in the generator in a thermal power station?

Answer 12

• turbine turns magnet inside generator

- kinetic → electrical energy

Question 13

6. What happens in the step up transformer in a thermal power station?

Answer 13

• voltage is increased

- electrical → electrical energy

Question 14

7. What do nuclear power stations produce?

Answer 14

-nuclear power stations produce radioactive waste

Question 15

8. What does radioactive waste emit?

Answer 15

-radioactive waste emits ionising radiation

Question 16

9. What can happen with increased exposure to ionising radiation?

Answer 16

-with increased exposure to ionising radiation, damage to living cells increases eventually leading to cancer (from damaging cells) or cell death (radiation poisoning)

Question 17

9. What is irradiation by a radioactive material?

Answer 17

-being exposed to the radioactive source without coming into direct contact with it

Question 18

9. What is contamination by a radioactive material?

Answer 18

• coming into direct contact with the radioactive source

e. g. breathing it in, getting it on skin

Question 19

9. Is irradiation or contamination by a radioactive material more harmful?

Answer 19

• contamination is more harmful

- can’t leave the area where you are exposed= exposed for a long period of time= higher dose

Question 20

11. What do renewable energy sources like wind power do?

Answer 20

-drive the turbine directly

Question 21

11. What are examples of energy sources that drive the turbine directly?

Answer 21

-hydroelectric, wave and wind

Question 22

13. What is the mains supply voltage to our homes?

Answer 22

-230 volts

Question 23

14. How is electricity distributed through the National Grid?

Answer 23

• electricity is distributed through the National Grid at high voltages to reduce energy losses
• as high voltage= low current so less energy is lost as heat through cables