Trilogy
1 Energy
Foundation Questions & Answers
Q1.
Figure 1 shows a battery operated remote control car.
Figure 1
© Brandon Bolin/iStock/Thinkstock
(a) The car’s battery contains a store of energy.
As the car moves, energy from one store is transferred to another store.
Describe how different stores of energy change as the car moves.
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(2)
(b) The car has a top speed of 12 m / s and a mass of 800 g.
Write down the equation that links kinetic energy, mass and speed.
Equation ___________________________________________________________
(1)
(c) Calculate the maximum kinetic energy of the car.
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Maximum kinetic energy = __________________ J
(2)
(d) Explain why having a more efficient motor increases the top speed of the car.
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(2)
(e) Figure 2 shows an electric car being charged.
Figure 2
By Alan Trotter Electric Car Charging [CC-BY-2.0]via Flickr
A driver wishes to buy a new car.
The table below gives some data about an electric car and one with a petrol engine.
Electric car Petrol engine car
Cost (£) 27 000 15 000
Running cost per year (£) 250 2 000
Average lifetime (years) 12 12
Which car would be the most economic over its 12 year lifetime?
Use data from the table above to support your answer.
You should include the difference in cost in your answer.
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(4)
(Total 11 marks)
Q2.
Electricity may be produced from a number of different energy resources.
(i) Complete the table below.
The first one has been done for you.
Device Energy Useful energy transfer
resource from resource
Coal-fired power station
Coal Chemical electrical
Hydroelectric power station
Stored __________ electrical
water
Solar cell in calculator
Sun __________ electrical
Wind turbine
Wind __________ electrical
Gas-fired power station
Gas __________ electrical
(4)
(ii) Give one of the five energy resources opposite, which is not classified as
renewable.
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(1)
(iii) State another non-renewable energy resource.
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(1)
(Total 6 marks)
Q3.
A student investigated the specific heat capacity of metals.
(a) Describe an experiment the student could do to measure the specific heat capacity
of a metal.
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(6)
(b) The student calculated the specific heat capacity of four metals.
The table below shows the student’s results.
Metal Mass of Time in Temperature Change in Calculated
material in minutes in °C thermal specific heat
kg energy in capacity of
J material
in J / kg °C
Aluminium 1 10 2 4 780 2 390
Brass 1 10 4 4 660 1 165
Copper 1 10 4 600 657
Steel 1 10 5 4 690 938
Use data from the table above to calculate the temperature change for copper.
Use the correct equation from the Physics Equation Sheet.
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Temperature change = ________________ °C
(3)
(c) What is the independent variable in the student’s investigation?
Tick one box.
Mass of material
Power used
Time in minutes
Type of material
(1)
(d) The student calculated the specific heat capacity of aluminium to be 2390 J / kg °C.
The ‘true’ specific heat capacity of aluminium is 900 J / kg °C.
Suggest why the student’s result for aluminium is different from the ‘true’ value.
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(2)
(e) The teacher suggested that putting bubble wrap round the metal block would
change the results.
How would using bubble wrap change the results?
Give a reason for your answer.
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(2)
(Total 14 marks)
Q4.
Electricity can be generated using various energy sources.
(a) Give one advantage and one disadvantage of using nuclear power stations rather
than gas-fired power stations to generate electricity.
Advantage __________________________________________________________
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Disadvantage _______________________________________________________
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(2)
(b) (i) A single wind turbine has a maximum power output of 2 000 000 W.
The wind turbine operated continuously at maximum power for 6 hours.
Calculate the energy output in kilowatt-hours of the wind turbine.
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Energy output = ____________________ kWh
(2)
(ii) Why, on average, do wind turbines operate at maximum power output for only
30% of the time?
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(1)
(c) An on-shore wind farm is made up of many individual wind turbines.
They are connected to the National Grid using underground power cables.
Give one advantage of using underground power cables rather than overhead
power cables.
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(1)
(Total 6 marks)
Q5.
Diagram 1 shows the energy transferred per second from a badly insulated house on a
cold day in winter.
Diagram 1
(a) (i) When the inside of the house is at a constant temperature, the energy
transferred from the heating system to the inside of the house equals the
energy transferred from the house to the outside.
Calculate, in kilowatts, the power of the heating system used to keep the
inside of the house in Diagram 1 at a constant temperature.
1 kilowatt (kW) = 1 kilojoule per second (kJ/s)
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Power of the heating system = ___________________________ kW
(1)
(ii) In the winter, the heating system is switched on for a total of 7 hours each day.
Calculate, in kilowatt-hours, the energy transferred each day from the heating
system to the inside of the house.
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Energy transferred each day = ___________________________ kWh
(2)
(iii) Energy costs 15 p per kilowatt-hour.
Calculate the cost of heating the house for one day.
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Cost = _______________
(1)
(iv) The heating system is switched off at midnight.
The graph shows how the temperature inside the house changes after the
heating system has been switched off.
Time of day
Draw a ring around the correct answer in the box to complete the sentence.
Between midnight and 6 am the rate of energy transfer from
decreases.
the house decreases then stays constant.
increases.
Give the reason for your answer.
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(2)
(b) Diagram 2 shows how the walls of the house are constructed.
Diagram 3 shows how the insulation of the house could be improved by filling the
air gap between the two brick walls with plastic foam.
Diagram 2 Diagram 3
U-value of the wall = 0.7 U-value of the wall = 0.3
The plastic foam reduces energy transfer by convection.
Explain why.
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(2)
(Total 8 marks)
Q6.
State and explain the advantages and disadvantages of using nuclear power stations to
produce electricity.
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(Total 4 marks)
Q7.
(a) An electricity company claims to generate all of its electricity from environmentally
friendly energy sources.
The energy sources used by the company are shown in the pie chart.
Do you think that the claim made by the company is correct?
Draw a ring around your answer.
Yes No Maybe
Explain the reasons for your answer.
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(2)
(b) The government is committed to increasing the amount of electricity generated from
renewable sources. A newspaper reported that:
Why is the statement made in the newspaper incorrect?
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(1)
(Total 3 marks)
Mark schemes
Q1.
(a) the store of chemical energy (in the battery) decreases
1
the internal energy of the surrounding air increases.
1
accept description of energy becoming less usefully stored
for 2 marks
(b) kinetic energy = ½ mass × velocity2
1
(c) EK = ½ × 0.8 × 122
1
EK = 57.6 (J)
1
allow 57.6 (J) without working shown for 2 marks
(d) lower proportion of wasted energy
accept less energy is wasted
1
higher proportion of energy is converted into kinetic energy
accept more kinetic energy
1
(e) Level 2 (3–4 marks):
A relevant and coherent argument which demonstrates processing and numerical
analysis of the information presented and draw a conclusion which is logically
consistent with the reasoning and refers to payback time for the vehicles.
Level 1 (1–2 marks):
Simple comparisons are made which demonstrate a basic ability to numerically
analyse
the information presented. The conclusion, if present, may not be consistent with the
calculations.
0 marks:
No relevant content
Indicative content
• The electric car costs £12 000 more to buy
• Running cost of electric car = £3 000
• Running cost of petrol engine car = £24 000
• Total cost of electric car = £30 000
• Total cost of petrol engine car = £39 000
• The electric car cost £1 750 less to run each year
• The electric car will save £9 000
• Additional cost is covered in 6.9 years
• So the electric car will be cheaper over the 12 year lifetime
or
Electric
27000 / 12 = 2250
Annual cost = 2250 + 250 = 2500
Petrol
15000 / 12 = 1250
Annual cost = 1250 + 2000 = 3250
So electric is £750 cheaper per year
4
[11]
Q2.
(i) gravitational or potential
do not accept stored
1
light
credit solar
1
kinetic or movement
credit moving
1
chemical
1
(ii) any one from
gas
coal
1
(iii) any one from
oil
do not accept petrol or paraffin
peat or turf
nuclear
credit coal or gas if not given as answer to part (ii)
do not accept wood or fossil fuel or chemical
1
[6]
Q3.
(a) Level 3 (5–6 marks):
A full, detailed and coherent plan covering all the major steps is provided, which
outlines what needs to be measured to calculate specific heat capacity. The steps
are set out
in a logical manner that could be followed by another person to calculate the specific
heat capacity.
Level 2 (3–4 marks):
The substantive content of a plan is present but may be missing some steps. The
plan
may not be in a completely logical sequence but leads towards the calculation of the
specific heat capacity.
Level 1 (1–2 marks):
Simple statements relating to relevant apparatus or steps are made but they may
not be
in a logical order. The plan would not allow another person to calculate specific heat
capacity.
0 marks:
No relevant content.
Indicative content
• measure the mass of metal
• correct use of balance
• description of how work is done or energy transferred to metal
eg electrical work, mechanical work (eg dropping lead shot)
• how energy transfer or work done is measured
eg electrical using joulemeter, mechanical decrease in
potential energy store of falling lead shot
• equate work done / energy transferred = increase in thermal energy store of
the
metal
• calculate specific heat capacity
6
(b) 4 600 = 1 × 657 × temperature change
1
temperature change = 4 600 / 657
1
= 7 (°C)
allow 7 with no working shown for 3 marks
1
(c) Type of material
1
(d) heat loss
1
then any one from:
• turned off the power supply too early
• incorrectly measured mass of material
• incorrectly measured temperature
• incorrectly read the change in thermal energy
1
(e) would give a more accurate value or the calculated specific heat capacity will be
smaller
1
because the bubble wrap insulates the material or prevents heat loss
1
[14]
Q4.
(a) advantage
any one from:
• produce no / little greenhouse gases / carbon dioxide
allow produces no / little polluting gases
allow doesn’t contribute to global warming / climate change
allow produce no acid rain / sulphur dioxide
reference to atmospheric pollution is insufficient
produce no harmful gases is insufficient
• high(er) energy density in fuel
accept one nuclear power station produces as much power
as several gas power stations
nuclear power stations can supply a lot of or more energy is
insufficient
• long(er) operating life
allow saves using reserves of fossil fuels or gas
1
disadvantage
any one from:
• produce (long term) radioactive waste
accept waste is toxic
accept nuclear for radioactive
• accidents at nuclear power stations may have far reaching or long term
consequences
• high(er) decommissioning costs
accept high(er) building costs
• long(er) start up time
1
(b) (i) 12 000 (kWh)
allow 1 mark for correct substitution eg
2000 × 6
or
2 000 000 × 6
or
an answer of 12 000 000 scores 1 mark
2
(ii) any idea of unreliability, eg
• wind is unreliable
reference to weather alone is insufficient
• shut down if wind too strong / weak
• wind is variable
1
(c) any one from:
• cannot be seen
• no hazard to (low flying) aircraft / helicopters
• unlikely to be or not damaged / affected by (severe) weather
unlikely to be damaged is insufficient
• (normally) no / reduced shock hazard
safer is insufficient
less maintenance is insufficient
installed in urban areas is insufficient
1
[6]
Q5.
(a) (i) 5(.0)
1
(ii) 35 or their (a)(i) × 7 correctly calculated
allow 1 mark for correct substitution, ie 5 or their (a)(i) × 7
provided no subsequent step shown
2
(iii) 525(p)
or
(£) 5.25
or
their (a)(ii) × 15 correctly calculated
if unit p or £ given they must be consistent with the numerical
answer
1
(iv) decreases
1
temperature difference (between inside and outside) decreases
accept gradient (of line) decreases
do not accept temperature (inside) decreases
do not accept graph goes down
1
(b) air (bubbles are) trapped (in the foam)
do not accept air traps heat
foam has air pockets is insufficient
1
(and so the) air cannot circulate / move / form convection current
air is a good insulator is insufficient
no convection current is insufficient
answers in terms of warm air from the room being trapped
are incorrect and score no marks
1
[8]
Q6.
Read all the answer first. See below.
Mark the first two advantages and disadvantages (√ or X) ignoring
neutral answers. Only allow a third advantage if there is only one
disadvantage given. Only allow a third disadvantage if only one advantage is given.
max. 3 advantages (e.g. cheap fuel, good availability, saving fossil fuels,
low running costs, reliable, more energy / kg, less fuel needed, no
greenhouse gases emitted, no SO2 causing acid rain)
max. 3 disadvantages (e.g. danger to health of local community, non
renewable, high cost of decommissioning, long half life of waste
materials, need for safe storage of waste, high cost of commissioning,
danger involved in transporting fuel / waste)
max. 4 marks
[4]
Q7.
(a) marks are awarded only for the reason but must match the
ringed answer
for both marks a MAYBE answer should include a YES and
NO response answers in terms of the sources being
renewable or
non-renewable are insufficient
any two from:
YES answers may include:
• wind produces no pollutant gases
accept wind burns no fuel
accept CO2 / SO2 / oxides of nitrogen / greenhouse gas for
pollutant gases
• nuclear produces no pollutant gases
accept nuclear burns no fuel
• (burning) gas does not produce SO2
accept gas does not cause acid rain
do not accept they don’t / none produce pollutant gases
NO answers may include:
• nuclear produces radioactive waste
• (burning) gas produces CO2 / pollutant gases / air pollution
accept contributes to global warming / greenhouse effect
2
(b) nuclear power stations use a non-renewable fuel
accept uranium / plutonium is non-renewable
do not accept some are unrenewable
1
[3]
