national and global energy resouces (topic 1)

Question 1

in the UK, most electricity is generated in power stations that burn fossil fuels, which type of fossil fuel power station has the shortest start-up time

Answer 1

gas

Question 2

(1)

Answer 2

transmission cables and step-up and step-down transformers

Question 3

a step-up transformer is used near the power station and increases the

Answer 3

voltage

Question 4

using a step-up transformer makes the distribution of electricity

Answer 4

more efficient

Question 5

use the graph to explain why the power output from the wind turbines was less than one sixth of the maximum

Answer 5

• one sixth of the maximum power output is 3000/6 = 500 which requires a wind speed of 6m/s
• average wind speed is below 6m/s making it less than one sixth of the maximum
• wind speed too low

Question 6

Answer 6

7600/950 = 8

Question 7

explain why allowing the surface of the solar panels to become very dirty will increase payback time (2)

the amount of time it will take for an investor to save as much money as their initial investment

Answer 7

• less electricity generated
• because lower light intensity hitting solar cell
• so decreases money gained from selling electricity

Question 8

which transformer, A, B, C or D will supply homes, offices and shops

Answer 8

D

Question 9

Answer 9

less than

Question 10

what is meant by potential difference

Answer 10

a measure of energy, per unit of charge, transferred between two points in a circuit

Question 11

Answer 11

a system of cables and transformers

Question 12

Answer 12

so fan reaches full speed

Question 13

(2)

Answer 13

• as the number of blades increases so does the voltage
• increase is directly proportional up to 3 blades
• it reaches a limit

Question 14

give a reason why ‘c’ is most likely to show the electrical power output from a wind turbine over one day (1)

Answer 14

• wind speed varies
• wind is not constant

Question 15

Answer 15

water

Question 16

Answer 16

water
heated
generator

Question 17

Answer 17

Question 18

solar farms can be used to produce large amounts of electricity, state one advantage and one disadvantage of using a solar farm to produce electricity (2)

Answer 18

• solar does not produce greenhouse gases such as carbon dioxide
• solar is a renewable energy resource
• does not produce electricity at night
• requires a large area to install solar farm

Question 19

(4)

Answer 19

• water held in the reservoir has gravitational potential energy
• when the reservoir is opened, the water flows and gravitational potential energy is transferred mechanically to the kinetic store
• the kinetic energy of the water is transferred to the turbine
• the turbine drives the generator which transfers energy to the National Grid electrically

Question 20

hydroelectric power stations can be used to meet sudden surges in demand during peak hours, discuss the advantages and a disadvantages of using hydroelectric power stations to meet this demand (4)

Answer 20

• hydroelectric power plants are renewable energy resources
• no greenhouse gases produced
• short start up time
  _
• construction of dam is expensive
• high risk of flooding

Question 21

Answer 21

Question 22

the wind turbine operates with an efficiency of 32%, calculate the power output of the turbine (kinetic energy = 998400m/s)

Answer 22

Question 23

state two advantages of moving away from using coal as an energy resource (2)

Answer 23

• coal is a non-renewable energy resource and will run out
• burning coal releases greenhouse gases such as carbon dioxide
• contributes to pollution

Question 24

Answer 24

nuclear

Question 25

describe the energy transfers that take place in this type of power station (4)

Answer 25

- nuclear energy in uranium transferred to the kinetic energy of fission products - kinetic energy of fission products transferred to thermal store of coolant - thermal store of coolant transferred to the thermal store of water - thermal store of water transferred to the kinetic store of steam - kinetic store of steam transferred to the kinetic store of the turbine/generator - kinetic store of turbine/generator transferred electrically to the National Grid

Question 26

describe two advantages and two disadvantages of using nuclear power (4)

Answer 26

**advantages (max 2 marks):** - no carbon dioxide emitted OR no greenhouse gases - does not contribute to global warming - reliable/not weather dependent - only small amounts of fuel required to provide a large **disadvantages (max 2 marks):** - difficult to dispose of waste - nuclear accidents can spread harmful radiation - decommissioning costs are high - nuclear fuel is toxic/harmful/radioactive/difficult to handle

Question 27

(3)

Answer 27

- fossil fuel usage has decreased each year from 2015 to 2020 - nuclear decreased slowly between 2015 and 2020 - the use of renewables has increased since 2015

Question 28

explain why the UK government is moving away from using fossil fuels and investing in renewables (3)

Answer 28

- fossil fuels are non-renewable energy resources, meaning they will run out - fossil fuels cannot be replenished - burning fossil fuels releases carbon dioxide - which contributes to global warming

Question 29

discuss the advantages and disadvantages of relying solely on solar power in the UK (4)

Answer 29

**advantages (max 2 marks):** - sunlight is free and so there are no fuel costs associated with solar panels - solar is renewable and won't run out - solar panels do not produce greenhouse gases or contribute to global warming - the homeowners energy bills will be reduced **disadvantages (max 2 marks):** - solar panels only produce electricity during the day / when illuminated - power output may be drastically reduced on cloudy days - power output will be lower in the winter months when there are fewer hours of daylight - solar panels are inefficient - solar panels are expensive

Question 30

the maximum output from fossil fuels was 25 GW, calculate how much electricity needed to be provided by nuclear or renewables at 20:00

Answer 30

- at 20:00 the demand for electricity was approximately 30 GW - electricity from renewables or nuclear = 30 - 25 = 5 GW

Question 31

explain why the proportion of non-renewable energy resources is decreasing in many countries (2)

Answer 31

- non-renewables will run out/cannot be replenished - burning fossil fuels releases greenhouse gases/contribute to global warming

Question 32

describe the energy transfers that take place in a geothermal power station (5)

Answer 32

- radioactive materials release energy heating rock deep within the earth - thermal energy from rocks in the ground is transferred to the thermal store of water in pipes - the thermal store of water is transferred to the kinetic store of steam - the kinetic energy of the steam drives a turbine connected to a generator - the generator distributes energy electrically via the National Grid

Question 33

describe the energy transfers that take place in a coal-fired power station (5)

Answer 33

- coal is a store of chemical energy - the chemical store of coal is transferred to the thermal store as it is burned - the thermal store of the coal is transferred to the thermal store of water - thermal store of water is transferred to the kinetic energy of steam - kinetic energy of steam is transferred to the kinetic energy of the turbine/generator - the generator transfers energy electrically to the National grid