Web viewaccept both have a turbine /generator / use steam. ... or energy/heat losses low ... or for...

M1. (a) kineticaccept movement

1

(b) (i) 3 (kWh)allow 1 mark for selecting the correct information

1

(ii) transfers more energyaccept transform or use for transferaccept electricity for energyallow higher (average) power and switched on for more time

2

(iii) any one from:

• use the internet

• brochures

• reading adverts

• visiting shops

• recommendation from friends / plumbers1

[5]

M2. (a) (i) gridaccept any way of indicating correct answer

1

(ii) increases voltageaccept any way of indicating correct answer

1

(iii) 230 Vaccept any way of indicating correct answer

1

(iv) reduce

accept any way of indicating correct answer1

(b) (i) increases the temperatureaccept make it hotter / heat goes into the airaccept convection currentsaccept sensible comment eg sound energy / it buzzesignore pollutes the air

1

(ii) less than 100%1

[6]

M3. (a) 9allow 1 mark for correct substitution(1.8 × 5)an answer of 9000 gains 1 markan answer of 2 or 15 gains 1 mark

2

(b) (3kW) fan heateraccept 3kWaccept the middle one

1

(c)features common to more than one heater, treat as neutral

oil-filled

low level heat

cannot be knocked over / space saving / no trailing wiresdo not accept just wall-mounted

or more control over heat outputdo not accept just 3 heat settings

1

fan

warms (office) rapidly or can be used to cool air (in summer)accept can be used as a fanaccept cool air fan (setting)accept ‘it has a cool air setting in case it gets too hot’do not accept a specific reference to cooling the heater

1

ceramic

can be switched on for set periods of timedo not accept just has a timer

or can be switched on before office is used / switched off automatically at night1

[6]

M4. (i) reducesfor 1 mark

1

(ii) less heat/energy/power wasted (in power lines)for 1 mark

1

(iii) for safetyfor 1 mark

1[3]

M5. (a) generatoraccept dynamo

accept alternator1

(b) (i) 1400ignore units

1

(ii) 0.3 or 30%any incorrect unit penalise 1 markallow 1 mark for the correct use of 600or 0.3% or 30

2

(c) 1 mark for each correct link

if more than 3 lines are drawn, mark only3 lines starting with those that are incorrect

3

(d) (i) 110no tolerance

1

(ii) 12no tolerance

1

(iii) wind speed may be too low to operate the generatoraccept wind may not always blowaccept power depends on wind speedaccept does not generate if wind speed is too highaccept does not generate if wind speed is above 12 (m/s)accept does not generate if wind speed is below 1.6 (m/s)accept it is unreliabledo not accept answers referring to cost only

1[10]

M6. (a) electrical1

soundcorrect order only

1

(b) the energy transformed by the TV will be destroyed1

(c) a higher efficiency than1

[4]

M7. (a) 1.8 (p)these 4 marks can be broken down as follows:1 mark for correct transformation and substitution into efficiency equationie 0.8 × 1200 – useful powerPLUS1 mark for useful power = 960 W / 0.96 kWPLUS1 mark for waste energy transferred = 0.24 × 0.5orwaste energy transferred = 0.12 (kWh)PLUS1 mark for cost = 0.12 × 15where a mathematical error has been made full credit should be given for subsequent correct method

4

(b) the waste energy is transferred as heat and sound1

to the surroundings where it spreads out / is shared bysurrounding particles

accept air for surroundings1

[6]

M8. (a) Using wind (advantage)

any one from

can be used in remote locations

renewable

cleanaccept does not cause pollution to the air / land

1

Using wind (disadvantage)

any one from

does not generate much (electrical) energymany hundreds wind turbines would be needed

accept many hundreds wind turbines would be needed or too much land would be needed for wind farms or wind energy is ‘dilute’

the wind is unreliableaccept the wind does not blow all of the time or the wind is not always strong enough

noise / visual pollutiondo not accept just the word pollution

1

Using coal (advantage)

any one from

can generate electricity all of the timeaccept reliable electrical / energy supply

generates a lot of (electrical) energy1

Using coal (disadvantage)

any one from

pollution by carbon dioxide / greenhouse gasaccept slow start-up time or production of ash or difficult to transport (coal) or there’s not much coal left

non renewable

pollution by sulphur dioxide acid rain1

(b) all link lines correctaccept one link line correct for one mark

2[6]

M9. (a) each correct line scores 1 mark

if more than 3 lines are drawn mark incorrect ones first, to a maximum of 3 lines

3

(b) toasteraccept 1.2 kW

1

(c) (i) 4001

(ii) £24 or 2400pfull credit for their (c)(i) × 6p for full credit the correct numerical answer must have the correct unitan answer of 24 or 2400 with no unit or the incorrect unit scores 1 mark(c)(i) × 6 incorrectly evaluated scores 1 mark

2

(d) 6allow 6000 for 1 markallow 3 × 2 for 1 mark

2[9]

M10. (a) £19.20allow 1 mark for correct substitutionie 160 × 12allow 1 mark for an answer (£)1920an answer of 1920p gains both marksan answer of £40.80 gains both marksallow 1 mark for 340 × 12

2

(b) 340allow 1 mark for correctly using the reading 62580 ie 62920 − 62580accept £40.80 for both marks

2[4]

M11. (a) gas1

oil1

(b) (both) use steam to drive a turbineaccept (both) use turbines to drive generatorsdo not accept both have a turbine /generator / use steammust describe a step in the processaccept heat / thermal energy transformed to kinetic / electrical energy

1

(c) 140 (°C)correct answer onlyallow 1 mark for method clearly shown on graphaccept a cross or other indication at correct position on the lineaccept correct descriptionaccept even if numerical answer is incorrect

2

(d) any one from:do not accept answers purely in terms of disadvantages of other methods except for fossil fuels are running out

• very large energy source / reserves

• no polluting / harmful gases producedaccept named gas CO2 SO2 NOx

accept reduces harmful carbon emissions

• reduces carbon emissionsaccept does not contribute to global warming

• no fuel needed

• energy is free

• can generate energy for a long timeaccept energy available for a long time

• renewable (energy source)

• fossil fuels are running outaccept it saves fossil fuels / non-renewableaccept reduces the amount of fossil fuels being burntaccept a named fossil fuelBetter for the environment / environmentally friendly

insufficientit is cheaper is insufficient

1[6]

M12. (a) (i) replaced faster than it is usedaccept replaced as quick as it is usedaccept will never run outdo not accept can be used again

1

(ii) any two from:two sources required for the mark

• wind

• waves(*)

• tides(*)(*)do not accept water / oceansaccept OTEC

• fall of wateraccept hydroelectric

• biomass

• geothermalaccept a named biomass / biofuel eg wood

1

(b) (i) any two from:

• increases from 20° to 30°

• reaches maximum value at 30°

• then decreases from 30°

• same pattern for each monthaccept peaks at 30° for both marksaccept goes up then down for 1 mark

ignore it’s always the lowest at 50°2

(ii) 864an answer of 108 gains 2 marksallow 1 mark for using 720 value only from tableallow 2 marks for answers 852, 816, 768, 825allow 1 mark for answers 106.5, 102, 96, 103 (.125)

3

(c) the solar cells will not meet demand at all times of the year / dayaccept to maintain a constant supply of electricity / energy

or to make up the shortfall in energy required at certain times of the year

or to be able to sell surplus electricity (to the National Grid)accept to provide energy at nightdo not accept because it’s cloudy on it’s own

1[8]

M13. do not give any credit for renewable or non-renewable or installation or decommissioning costs

fossil fuel advantage1

a reliable source of energy

fossil fuel disadvantage

pollution by carbon dioxide /accept causes acid rainaccept highest costs / more expensive than nuclear / more expensive than renewable

1

nuclear advantage

do not produce gases that increase the

greenhouse effect or cause acid rainaccept nuclear is cheaper than fossil

1

nuclear disadvantage

accidents / waste can release very dangerous radioactive material radiationaccept it produces waste that stays dangerously radioactive for thousands of years or radioactive waste has to be stored safely for thousands of years

1

renewable advantage

there are no fuel costsalmost pollution free (apart from noise and visual)accept cheaper than fossil

1

renewable disadvantage

not a reliable source of energy except for hydroelectricaccept (most) require large areas of landaccept visual / noise pollution

1[6]

M14. (a) only accept answers in terms of the argument of the nuclear power scientist any three from:

• produces a lot of energy for a small mass of fuel or is a concentrated energy source

accept amount for mass

• it is reliable or it can generate all of the time

• produces no pollutant gasesaccept named gas or greenhouse gases do not accept no pollution

• produces only a small volume of (solid) wasteaccept amount for volume

• advances in technology will make fuel reserves last much longeraccept an argument in terms of supply and demand

3

(b) any one from:

• may leak into the ground / environment

• geological changesaccept earthquakes etc

• may get into the food chaindo not accept answers in terms of property prices or ‘damages the environment’

• over time if location not correctly recorded it may be excavated1

(c) any three from:

• overall add no carbon dioxide to the environmentaccept do not add to global warmingaccept they are carbon neutral

• power companies can sell electricity at a higher priceaccept power companies make more profit

• opportunity to grow new type cropaccept specific examples e.g. growing plants in swampsaccept extends the life of fossil fuel reserve

• more jobs

• more land cultivated or different types of land utilised3

[7]

M15. the higher the voltage the smaller the currentsmall current gives small energy lossin the form of heat(or efficiency greater, or energy/heat losses low – gets 1)

for 1 mark each

E1. In part (a) the vast majority of the candidates showed an understanding of energy transfer and many successfully achieved maximum marks for the calculation in part (b)(i). However, the cost implications of using different power cycles for the washing machine were not widely understood and many candidates were unable to describe how they would undertake research to compare the energy efficiency of domestic appliances. The candidates that were successful generally stated using the Internet.

E2. In part (a) most candidates could score 2 out of the 4 marks. Surprisingly few candidates knew the voltage of the mains.

In part (b)(i) only the better candidates realised that the waste energy would go into heating the air. An alarming number of candidates thought that the air would become radioactive, electrified, polluted with carbon dioxide or filled with thick black smoke. The most common incorrect answer was simply that it ‘pollutes the air’. In part (b)(ii) just over half of all the candidates made the correct choice.

E3. Foundation Tier

(a) Most candidates could substitute the correct numbers into the equation, although some erroneously put in a figure of 8 hours instead of 5. The most common mistake was to fail to convert 1800 watts into 1.8 kilowatts, thus arriving at an answer of 9000 instead of 9.

(b) Many candidates chose the ceramic heater, perhaps because it appeared to have the largest number attached to it.

(c) Most candidates were able to score at least one mark on this question, although very few scored all three marks. The most common mistake was simply to pick a feature from the illustration and copy it down. These candidates failed to realise that (i) it should be a feature not possessed by either of the other two, and (ii) that they should explain why this feature is an advantage.

Higher Tier

(a) A large number of candidates scored at least 1 of the 2 marks, common mistakes were a failure to convert from W to kW, or wrongly converting by dividing by 100. A surprising number of answers used the time as 8 hours, presumably because of the 8-hour timer. It would appear that many candidates do not read the questions thoroughly.

(b) This was well answered on the whole, although it appeared that some candidates just looked for the highest number, regardless of units.

(c) Many marks were lost by candidates not comparing each heater with the other two, again an example of not reading the question thoroughly. Good answers explained why the feature would be an advantage rather than just picking out a statement from the lists given.

E4. This question was moderately well answered but a minority of candidates were guessing or used language which was too vague to gain the marks. A very small number related 50 Hz to 50 ‘somethings’ per minute.

E5. Parts (a) and (b)(i) were well answered.

(ii) Many candidates inverted the figures before calculation or gave a unit to their final numerical answer.

(c) The noise problem of wind was usually given correctly but many candidates transposed the problems of hydro-electricity and tides.

(d) Most candidates identified the maximum power from the graph but many went on to state that the generator stopped working at 8 m/s because the graph line became horizontal at that point. The unreliability of wind generators was widely known.

E6. (a) The vast majority of candidates knew that a television is designed to transform electrical energy into light and sound energy.

(b) Most candidates could identify the false statement from the list.

(c) Most candidates realised that wasting less energy leads to a higher efficiency.

E8. (a) Candidates displayed a good understanding of the advantages and disadvantages of using wind and coal. The main problems were again, either using a vague statement such as ‘no pollution’ as the advantage of using wind, or simply repeating information already given such as ‘coal generates 1000MW’ as the advantage of using coal.

(b) This was usually completed correctly.

E9. (a) Most candidates showed a good working knowledge of the useful energy produced by a domestic electrical device, although a number of candidates believed that fans usefully produced heat and toasters light.

(b) Candidates were less adept at differentiating between watts and kilowatts. Rather surprisingly there was a small number of ‘personal stereos’ given for the answer which is difficult to understand.

(c) Although this part produced many correct readings of the domestic electricity meter, candidates seemed to experience difficulty in multiplying the numbers in parts (c)(ii) and (d) to successfully provide a cost for the electrical consumption or the energy transferred by the electric cooker.

(d) The answer 6000 for this part was much more common than 6.

E10. (a) Although many candidates could correctly manipulate the data to arrive at the figure 1920, many candidates either omitted the decimal point or omitted to state whether the figure was in pounds or pence. Some candidates are apparently unperturbed at the prospect of paying a quarterly bill of £1920.

(b) A third of candidates were able to work out the correct value of 340 kilowatt-hours. Many candidates incorrectly added the two readings together.

E11. (a) Most candidates correctly chose gas and oil as being the two energy sources likely to be used up first. A few candidates ignored the rubric and selected more than two energy sources.

(b) Many answers to this question were very vague, such as “they both have turbines”. The correct response required a reference to a step in the process.

(c) A well-answered question, with the majority of candidates obtaining the correct answer of 140 °C. Some candidates misread the scale and gave a wrong answer of 40 °C.

(d) Candidates usually realised that one advantage of geothermal energy was either that it saved using fossil fuels or that it is a renewable energy source. Some candidates simply restated the question, saying that the scientists would tell the government that this method could generate one quarter of the world’s electricity.

E12. (a) (i) Most candidates correctly identified renewable energy as a source which does not run out. Some candidates continued to say that it was replaced as quickly as, or more quickly than, it was used. The most frequently seen incorrect answer was to say that the source could be used again.

(ii) A well answered question with most candidates able to successfully identify two renewable energy sources. If the mark was lost it was mostly for including solar (which was given in the question) or for simply using the word water.

(b) (i) Whilst the majority of candidates correctly selected the maximum energy input at an angle of 30°, few responded in terms of the pattern of increase to and decrease from this maximum.

(ii) Some candidates completed the calculation correctly to obtain all 3 marks. Most candidates made a start on the calculation but common mistakes were to use the average energy input rather than the maximum, to overlook the area of the solar cells, or to divide the energy input by 0.15 instead of multiplying.

(c) Most candidates were able to successfully make the link between the amount of energy required and that provided by the solar cells, realising that the National Grid would be needed to supply the shortfall. A small number of candidates evidently did not know what the National Grid was and some thought the purpose of remaining connected was to monitor the household use of electricity. Some gave the impression that they thought the National Grid was the only way to get electricity or that this was needed to ensure safety and/or the correct voltage.

E13. Several marks could have been obtained by using comparative costs from the table but most candidates ignored it or gave only partially correct answers such as, ‘renewable is cheaper than nuclear’. References to environmental effects were usually on the level of ‘it is cleaner / dangerous’, rather than referring to specific pollutants such as carbon dioxide, sulphur dioxide and radioactive waste.

E14. Part (a) was not well answered with almost 50% of candidates scoring no marks. Many candidates wrote negatively about fossil fuels rather than about the merits of nuclear fuel. There were many vague comments about a lot of energy, with the stronger candidates being able to relate this to the amount of fuel being used. Some candidates wrote about reliability but some did not gain credit due to the vagueness of their answers.

The vast majority of candidates gained no credit in part (b) most ignored the fact that the waste was buried deep, or that it would be in any way contained.

In part (c) some candidates did not use the information they had been given and others ignored the question’s emphasis on the power companies. Many candidates did not distinguish between biofuels and electricity, thinking the power company would be selling the biofuels. The idea of carbon neutral was well identified by stronger candidates, but the weaker ones did not appear to be aware that burning biofuels also gives rise to carbon dioxide emission. A large number of candidates (40%) were unable to use any of the information presented to them and gained no credit at all.

E15. Many candidates scored a mark for recognising that electrical energy was transferred at high voltage to reduce energy losses or because it was more efficient. Far fewer gave the full explanation of high voltage being accompanied by low current and that low current resulted in low heat losses from the transmitting cables.

Web viewaccept both have a turbine /generator / use steam. ... or energy/heat losses low ... or for...

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