Oxford Revise AQA GCSE Physics | Chapter P3 answers

P3: National and global energy resources

Question

Answers

Extra information

Mark

AO / Specification reference

01.1

temperature change = 20 °C – 4 °C = 16 °C

energy transferred = mass × specific heat capacity × change in temperature

= 0.5 × 3930 × 16

= 31 440 J/3.1 × 104 J

1

1

1

AO2

4.1.1.3

01.2

to keep the inside of the refrigerator cool/at 4 °C

by slowing the transfer of thermal energy from the outside to the inside of the refrigerator

1

1

AO2

4.1.2.1

01.3

a low thermal conductivity

so that the energy transfers very slowly across the material

1

1

AO3

4.1.2.1

01.4

a refrigerator with a high efficiency rating has insulation material with a low thermal conductivity

because less electricity is used so less energy is wasted

accept reverse argument

1

AO3

4.1.2.1

4.1.2.2

02.1

the data are not continuous

the names are categoric

1

1

AO2

02.2

one in 1990

three in 2017

accept three times as many in 2017 than in 1990 for 2 marks

1

1

AO2

4.1.3

02.3

total fossil fuels in 1990 = 230 + 20 + 0 = 250

total fossil fuels in 2017 = 20 + 10 + 140 = 170

change = –80 (TWh)

1

1

1

AO2

4.1.3

02.4

coal

plausible reason e.g., coal more expensive/less available/too polluting/causes global warming or greenhouse gases

1

1

AO2

AO3

4.1.3

03.1

the cost of production of solar cells/photovoltaic cells is very high

1

AO1

4.1.3

03.2

the cheapest method is coal

which produces the highest mass of CO2 per unit

CO2 is a greenhouse gas/contributes to climate change/global warming

1

1

1

AO2

AO3

4.1.3

03.3

two from:

  • there are other considerations such as nuclear fuel produces radioactive waste
  • nuclear accidents cause radioactive material to be released
  • which could have a significant impact on the environment

one for each correct answer up to a maximum of two marks

2

AO3

4.1.3

03.4

(biomass involves) growing plants

plants take in CO2 from the atmosphere

which would lower the concentration of CO2/reduce the greenhouse effect/effects of climate change/idea of carbon neutral

1

1

1

AO2

AO3

4.1.3

04.1

points should be plotted at:

(0, 0), (2, 0), (4, 0.1), (6, 1.2), (8, 2.4), (10, 3.6), (12, 3.6), (14, 3.6)

one mark for correct variable on the x-axis and y-axis

one mark for appropriate scale on the x-axis and y-axis

one mark for three or four points of data plotted correctly

two marks for all data points plotted correctly

one mark for drawing a line of best fit

5

AO2

AO3

4.1.3

04.2

for small wind speeds the output is zero

as the wind speed increases, the output power increases

for a wind speed over 10 m/s, the power output doesn’t change/is constant

1

1

1

AO2

4.1.3

04.3

advantage – no greenhouse gases produced while it is in use/renewable resources/can be used in remote places

disadvantage – wind speed is variable/wind doesn’t always blow/needs a large space/noisy

1

1

AO1

4.1.3

05.1

independent – number of sheets of transparent film

dependent – energy per second

1

1

AO2

4.1.3

05.2

three from:

  • the distance of the lamp from the solar cell
  • the angle of the solar cell
  • the type/thickness of transparent film
  • the type/area of solar cell

one mark for each correct answer up to a maximum of three marks

3

AO3

4.1.3

05.3

statement one: do not incorporate 2.11 into the calculation of the mean/change mean to 3.65/repeat test

statement two: add units to columns 2/3 and change mean to mean energy per second (J/s)

statement one: change all the measurements to the same number of significant figures/three significant figures.

1

1

1

AO3

4.1.3

05.4

uncertainty = ± \(\frac{{{\rm{(4}}{\rm{.32}} – {4}{\rm{.12)}}}}{2}\)

= ± \(\frac{{{0}{\rm{.2}}}}{2}\)

= ± 0.1 J/s

1

1

AO2

4.1.3

06.1

a renewable resource can be replenished as it is used, but a non-renewable resource cannot

1

AO1

4.1.3

06.2

Resource

Used to generate electricity

Used as a fuel in cars

Is a renewable resource

coal

biomass

oil

wind

one mark for each correct column

3

AO1

AO2

4.1.3

06.3

non-renewable resources are very reliable/can produce a more/steady supply of electricity

1

AO2

4.1.3

07.1

wind/wave/hydroelectric/geothermal/solar/biofuel

1

AO1

4.1.3

07.2

in 1990, the total kWh for these resources was 225 million kWh, out of a total of 250 million kWh

so percentage = \(\frac{{{225} \times {100}}}{250}\) = 90%

in 2015 there were 190 million kWh out of 225 million kWh

so percentage = \(\frac{{{190} \times {100}}}{225}\) = 84.4%

The percentage has decreased/so has the overall energy use

accept 230 million kWh, giving 92%

1

1

1

1

1

AO2

AO3

4.1.3

07.3

change in energy use in 5 years = 230 million kWh – 250 million kWh = –20 million kWh

rate of decrease = \(\frac{{{\rm{20\ million\ kWh}}}}{{{\rm{5\ years}}}}\) = 4 million kWh/year

current use = 230 million kWh hours, half of this is 115 million kWh

number of years = \(\frac{{{\rm{115\ million\ kWh}}}}{{{\rm{4\ kWh\ per\ year}}}}\) = 28.8 years

accept 4 with no working for one calculation mark

accept 29 with no working for one calculation mark

1

1

1

1

AO3

4.1.3

07.4

sensible suggestions:

  • the energy use might halve in this time because people use more energy efficient devices/want to save money
  • the energy use might not halve in this time because this is an estimate based on past data/you cannot be sure that the downward trend will continue / world population is increasing

1

1

AO3

4.1.3

08.1

annual energy required by the village = 7000 × 106 × 60 min × 60 sec

= 2.52 × 1013 J (2.5 × 1013 to two significant figures)

1

1

AO2

4.1.3

08.2

energy generated by one turbine per year = 33 000 W × 60 sec × 60 min × 24 h × 365 days

= 1.04 × 1012 J

so you would need \(\frac{{{2}{\rm{.52}} \times {1}{{0}^{18}}}}{{{1}{\rm{.04}} \times {1}{{0}^{12}}}}\) = (24.2)

25 wind turbines

1

1

1

1

AO2

4.1.3

08.3

25 × 1 million = £25 million

7000 MWh = 7 000 000 kWh

total cost = 7 000 000 × £0.50

= £3.5 million

biofuel is cheaper

1

1

1

1

AO3

4.1.3

08.4

Level 3: Both resources evaluated, with at least one advantage and disadvantage of both given.

5-6

AO3

4.1.3

Level 2: Both resources evaluated, but an advantage or disadvantage missing for one resource.

3-4

Level 1: Only one resource evaluated, or only advantages or disadvantages given.

1-2

No relevant comment.

0

Indicative content:

  • both resources are renewable
  • biofuels are reliable
  • biofuels could be carbon neutral/carbon dioxide released by burning fuel (theoretically should) equal the carbon dioxide absorbed from the atmosphere by the living matter
  • however, carbon dioxide also produced during the process to make and transport biofuels
  • biofuel would contribute to climate change by producing CO2.
  • wind turbines can be noisy
  • wind turbines are not reliable, as only produce electricity when it is windy
  • wind power does not contribute to climate change/ no pollutant gases

09.1

two from:

  • oil
  • coal
  • gas

one mark for each correct answer up to a maximum of two marks

2

AO1

4.1.3

09.2

suitable resource e.g., hydroelectric, tidal power

correct description e.g., water in a lake moves down a hill/mountain

through a generator that produces electricity

1

1

1

AO1

AO2

4.1.3

09.3

two comments e.g.,

tides happen regularly/twice a day

water can be released from a lake on demand

or

the height of tides varies

rainfall to fill the lake is variable

one mark for each correct comment up to a maximum of two marks

2

AO3

4.1.3

09.4

carbon dioxide is a greenhouse gas

it contributes to climate change/causes global warming

1

1

AO1

4.1.3

09.5

power station affects habitats of wildlife

accept any suitable comment

1

AO2

4.1.3

10.1

gravitational potential energy = mass × gravitational field strength × height

1

AO1

4.1.1.2

10.2

60 × 9.8 × 10

= 5880 J

1

1

AO2

4.1.1.2

10.3

(extension =) 10 – 3.2 = 6.8

5880 J = 0.5 × k × 6.82

(spring constant =) \(\frac{5880}{{{\rm{(0}}{\rm{.5}} \times {6}{\rm{.}}{{8}^{2}})}}\)

= 254.33

= 254 N/m

1

1

1

1

1

AO1

AO2

4.1.1.2

Loading...