Energy Extra Questions Mark schemeM1.          (a)     (i)      vacuum

do not allow stopper1

(ii)     (absence of particles) means no (transfer of energy between)particles for conduction

accept particles or atoms or molecules or electrons1

         no movement of molecules for (transfer of energy by) convectionaccept particles/atoms/electronsif answer to (a)(i) is correct: then in (a)(ii) have stated‘conduction and convection both need a medium/particles/materials’ = 2 marks(If medium is specified, it must be correct, conduction can be solid, liquid or gas, convection must be liquid or gas)if answer to (a)(i) is incorrect then in (a)(ii) have stated ‘conduction and convection both need a medium...’= 1 mark, unless further qualified by stating about absence of particles, in which case get a second mark.

1

(b)     (i)      silvered surfaceaccept silver surface

1

(ii)     silvered is a bad emitter/radiator1

         surface reflects heat/energy/radiation (at inner and outer surface)or is a bad absorber (of energy)

accept bounces off1

[6]

 

 

M2.          (a)     (i)      15*

(ii)     60*

[* if incorrect but (ii)>(i) and (i) + (ii) = 75 then credit 1 mark]

(iii)     25each for 1 mark

3

(b)     stove because         more of the energy heats up room / heats the room moreorless energy escapes up chimney / less energy wasted

[Do not allow ‘less waste’ with the stove]orno un burnt fuel in smokereason for 1 mark

1[4]

 

 

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          (a)     60

(b)     15

(c)     5each for 1 markcredit 1 mark for (a) +(b)+ (c) = 80or (a) > (b) > (c) to maximum of 3

[3]

 

 

M4.         

each for 1 markallow ‘error carried forward' to the last box’

[3]

 

 

M5.          (a)     (i)      65

(ii)     5

(iii)     30

          [credit 1 mark if (i) + (ii) + (iii) = 100 or if (i) > (iii) > (ii)]for 1 mark each

3

(b)     heating local schools saves 16+ J / 16.25

          better cables saves 2.5 J

          better lamps saves 2.4 J (out of each 100 J)for 1 mark each

          best to use waste heat to heat schoolsfor 1 mark

4

          (NB credit answer consistent with own calculations – even if theseincorrect but must be based on at least 2 derived figures)

(c)     (i)       / 0.03(3) / 3(.3)%

         (credit correct fraction even if incorrectly converted to %)

(ii)      / 0.1 / 1%for 1 mark each

2[9]

 

 

M6.          (a)     (   B)(      )(A C)

          A = B  or  A/B = 20gains 1 mark

          but A = B = 20gains 2 marks

          A + B + C = 100for 1 further mark

          or C = 603

(b)     evidence of  or 20%/0.2 gains 1 mark

          but 25%/0.25 or figure consistent with B in part (a)gains 2 marks

2

(c)     ideas that“lost” energy is (also) transferred (in ways we don’t want) total amount of energy (before and after any transfer) remains the sameenergy becomes (progressively) more spread out/less easy to transfer againthis applies to all the energy/even to the energy usefully transferred

each for 1 mark4

[9]

 

 

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          (a)     cooking and heating water 30heating rooms 50

each for 1 mark2

(b)     coalidea that amount used fell/declined/line goes down

gains 1 mark

          but idea that fall/decline is steady/gradually/approx halvedgains 2 marks

          gasideas thatamount used rose/increasedin/from 1980/more used before 1980/ref to 1980        as an important date/rapid increase in use(credit idea that gas>coal from c.1990in either part with 1 mark (to maximum 4)

each for 1 markmax 4

(c)     •    less carbon dioxide produced

•        less change to weather/food production/gainedwarming/water levels (no mark for “greenhouse gas” alone)

•        no/less sulphur dioxide produced/coal produces sulphur dioxide

•        less acid rain/damage to fish/buildings/trees/crops/animals/tumours etc(do not credit reference to cost unless : cheaper so can spend more on environment)

(“It” used in an answer will refer to “gas”) any 3 for 1 mark each

3[9]

 

 

M8.          (a)     (i)      …….. light …… electrical2

for 1 mark each

(ii)     …….. electrical……chemicalfor 1 mark each

2

(iii)     …….. electrical ….. kineticfor 1 mark each

2

(b)     (i)      1500 / 10gains 1 mark

1

         but150

gains 2 marks1

(ii)     heat (thermal) or soundfor 1 mark

1[9]

 

 

M9.          (a)     sectors closer to correct value than ± 1% nuclear (5%)gas 24% moving water 1%

each for 1 mark maximum of 2 marks

3

          sectors labelled correctly w.r.t. rank order of sizefor 1 mark

          But deduct 1 mark if not all sectors used

(b)     5 × as much     (do not credit simply more/4% more)4 × as much

1

(c)     wind/waves/solar/tides(allow geothermal/wood/biomass)

any one for 1 mark1

(d)     idea thatelectricity is a secondary/man made source/needs anothersource to produce it

for 1 mark1

[6]

 

 

M10.          (i)      gravitational or potentialdo not accept stored

1

          lightcredit solar

1

          kinetic or movementcredit moving

1

chemical1

(ii)      any one from

gas

coal1

(iii)     any one from

          oildo 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]

 

 

##

          (a)     sectors nearer to correct value than to 1% either sidecoal                      35%nuclear                  5%gas                       24%moving water        1%

each for 1 mark -to a maximum of 3 marksdeduct 1 mark if sector left blank

three sectors labelled correctly w.r.t. rank order of sizefor 1 mark

4

(b)     (fossil) fuels (allow combustible/flammable/non renewable) 1

(c)     moving water/hydrowind/waves/tides/solar (allow geothermal/wood/biomass)

each for 1 mark2

(d)     any indication that we get more (energy from nuclear sources) gains 1 mark

          but5 times  as much/more

gains 2 marks2

[9]

 

 

M12.          (a)     mark independently

(from) gravitationalaccept potentialdo not credit stored

1

(to) kineticaccept movement

1

(b)     advantage

          * the current can be low (for the same power)* less energy or heat loss or  power loss

accept the cables do not have to be (so) thick accept less cost to support higher (rather than heavier) cablesaccept aluminium can be used and aluminium is cheaper than copperdo not credit efficient or cheaperdo not credit no loss of energydo not credit electricity loss

2

disadvantage

          * it is difficult to insulate high voltage* pylons have to be taller and so more expensive

...to give a good separation between them and the ground /people/high vehiclesor ... to prevent/reduce the danger of electric shock or lethal do not credit dangerousdo not credit get a shockdo not credit reference to step down transformers or electromagnetic field

2[6]

 

 

M13.          (a)     (heat) is conducted through the glassthe answers must be within the context of the question

1

          (heat) passes through glass and air by radiationboth glass and air required

1

          (heat) crosses the air gap by convectionmention of conduction through air is neutral

1

(b)     any one from

          lightaccept sunlight

gamma rays

X-rays

radioaccept sound or ir or microwaves or electromagnet waves

1

(c)     any two from

          cuts down convection currentsaccept stops air moving

air pockets trap air (from moving)accept has air pocketsdo not accept stops heat moving or traps heat

foam is a poor conductorair in the foam is a good insulatoraccept air is a good insulator in air pockets for both marks

2

(d)     evaporation (of the water)do not accept rain is cold

1

takes energy from the houseaccept takes heat away or higher energy molecules leave first

1[8]

 

 

M14.          (a)     (i)      hot water rises (not heat)for 1 mark

         due to convection currentsor water expands/becomes less dense on heatingor less dense water rises

any for 1 mark 2

(ii)     inside hotter (than outside)for 1 mark

1

(iii)     (heat transfer by) conductionfor 1 mark

1

(iv)    surround/cover/insulate tank with poor conductor or named insulatorfor 1 mark each

2

(b)     (i)      air is an insulator/poor conductorfor 1 mark

1

(ii)     convection stopped foam is an insulator/poor conductorfor 1 mark each

2[9]

 

 

M15.          (i)      D, C or B, in either order, then Atick or cross on the A

1

(ii)      matt absorbs energy (better than shiny)the converse arguments are acceptable

1

          black absorbs energy (better than white)1

[3]

 

 

M16.          (a)     insulationallow example e.g fibreglass

1

double glazingallow curtains

1

draught excluder

allow double glazing / close fitting doorallow turning down thermostat once only / turn down the heating

1

(b)     transfers more useful energyallow converts more energy into light / less into heat / less energy wasted

1[4]

 

 

M17.          (a)     (i)      201

(ii)     convection1

(iii)     fit draughtproof strips1

accept lay carpetaccept fit curtainsaccept close doors / windows / curtainsaccept any reasonable suggestion for reducing a draught‘double glazing’ alone is insufficient

(b)     air is (a good) insulator1

or air is a poor conductoraccept air cavity / ‘it’ for air

reducing heat transfer by conductionaccept stops for reducesignore convectiondo not accept radiationdo not accept answers in terms of heat being trapped

1

(c)     (i)      most cost effectiveaccept it is cheaper or lowest costaccept shortest payback timeaccept in terms of reducing heat loss by the largest amount

do not accept it is easierignore most heat is lost through the roof

1

 (ii)    41

[7]

 

 

M18.          …….. conduction…….. convection…….. insulation…….. radiation

for 1 mark each[4]

 

 

M19.          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]

 

 

M20.          (a)     SunAny valid

for 1 mark each2

(b)     From electric/pe or chemical in batteryfor 1 mark

to ke, light, sound, heat3 for 1 mark each

4

(c)     Gravitational pe OR just peFor any gravity feedOR Elastic peany validOR FoodFor maintaining body/life etc.OR Any descriptive answere.g. water in a high lake used to produce hydroelectric power

2 for 1 mark each2

[8]

 

 

M21.          (a)     (i)      Carries heat up (as convection current)1

(ii)     (1) By conduction or from molecule to molecule(2) By radiation or as IR

2

(iii)     Use shiny surface (inside or outside) or small area1

(b)     (i)      Rise more quickly1

(ii)     Dull surface good absorber(accept “attract” = “absorb” if context correct,then penalise spg mark.

Shiny surface poor absorber2

(c)     (i)      Fall more quickly1

(ii)     Dull surface good emitterShiny surface poor emitter

2[10]

 

 

M22.          (a)     energy needed to produce evaporation comes from the body1

therefore this stops the body temperature rising1

(b)     the silver space blanket reflects energy back to the runneraccept heat for energy

1

and this reduces the energy transferred from the body by radiation1

[4]

 

 

M23.          (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]

 

 

M24.          (a)     60for 1 mark

1

(b)     electrical to lightgains 1 mark

          but electricity to light and heat gains 2 mark

          anything to heat and light gains 1 mark

2

(c)     (unwanted) heat producedfor 1 mark

1[4]

 

 

M25.          (a)     plastic/glass walls; vacuum; insulating topany two for 1 mark each

2

(b)     silvering/shiny on either wallfor 1 mark

1[3]

 

 

M26.          (a)     the outside colour of the cans1

(b)     (i)      18 (°C) or 88 to 70ignore negative sign

1

(ii)      8 (°C) or 70 to 62ignore negative sign

1

(c)     greater temperature difference between water and surroundings (at start)must mention temperature differenceignore just water hotteraccept energy used to heat cans initially

1

(d)     black1

temperature falls the fastest (in L)accept (can L) loses more heat / cools quickeraccept heat for temperature

1

black is a good / the best / better emitter (of heat / radiation)accept converseignore black is best absorber

1[7]

 

 

M27.          (i)      radiation or infra reddo not accept raysdo not accept wavesaccept electromagnetic waves

1

(ii)      good absorber (of heat) to absorb heat (or infrared)do not accept ‘attract’ or ‘capture’ or soak

1

(iii)     reduce heat loss (from the panel)accept (good) (heat) insulatoraccept stop or reduce conductionaccept stop or reduce convectionaccept traps heataccept keeps water hot

1

(iv)     to reflect (back into the panel) heat or infrared or Sun’s energydo not accept ‘bouncing’do not accept reflect Sun

do not accept reflect sunlight or sun’s rays1

          radiated or given out by the (black) pipeaccept back to pipeaccept reduce heat loss for 1 markaccept reduce heat loss by radiation for 2 marksaccept stop heat loss by radiation for I mark

1[5]

 

 

M28.          (a)     (i)      photosynthesis for growthaccept plants require sunlight for growth

1

plants change into coalany mention of animals negates second mark

1

(ii)     burningdo not accept heatingaccept combustion

1

          (b)     (i)      heat1

(ii)     less heat radiated into spaceaccept increased insulation round earthaccept reflects heat back to earthaccept greenhouse effectaccept traps heat or energy

1[5]

 

 

M29.          any one from:basic idea of reduced use of fuels to heat homes or offices or shops for 1st mark

          less (heat) energy wasted (to the environment)

          reduced demand for fuels to heat homes etcsimply re-quoting figures gets no credit

1

          any one from:idea of less pollution for the 2nd mark

          reduced (air) pollutiondo not accept no pollution

          fewer power stations required or less electricity needs to be produced

          less (fossil) fuels being burnt (in power stations)

          reduced greenhouse effect

          reduced global warming1

[2]

 

 

M30.          (a)     (i)      sources of energyfor 1 mark

(ii)     wood      coal              oil               gas

all correct gains 2 marks3 correct gains 1 mark

3

(b)     geothermal      nucleartideswindsolar

all correct gains 2 marks4 correct gains 1 mark

2

(c)     non-renewable fuels cause pollution (or reverse)conserve/limit use of coal/gas/oil;so supplies last longer/renewable sources can be replaced

any 2 from 4 for 1 mark each2

[7]

 

 

M31.          (a)     (i)      convection current correctly shownwith arrows extending to aboveinsulation label line

circulation must show water rising in the left half of the tank accept continuous or broken arrows must be at least one arrow up and one arrow downallow 1 mark for correct diagram which does not extend high enough

2

(ii)     it expands or it gets less densedo not allow hot water risesdo not accept explanation in terms of molecules expanding or changing densitydo not accept lighter or heavier

1

more dense water fallsallow cold water falls if qualified with a suitable reason

1

          (b)     (i)      reflects heat back into the room or where it came fromaccept infrared or radiation or energy for heataccept bounce for reflect if in correct context

1

(ii)     air is a (good) insulator or poor conductor or air stops conductiondo not accept plastic foam is a good insulator  or bad conductor

1

air is trapped1

convection loss reduced or stopped1

(c)     two out of the following three:any answer which gains credit must contain a comparison

rate of evaporation decreases

accept less sweat can evaporate or evaporation is more difficult

          less heat energy removed from the body

          higher humidity the less water vapour can be absorbed (into the air)accept sweat for water vapourdo not credit description of high humidityaccept a correct answer in terms of dynamic equilibrium

2[10]

 

 

M32.          (a)     (i)      as a source of thermal radiationaccept heat for thermal radiationaccept to act as the Sundo not accept sunlight alone

1

(ii)     any one from:

•        volume of wateraccept amount for volume

•        distance between lamp and boiling tube

•        initial / starting temperature of water

•        same room temperaturedo not accept time or same insulation material

1

(iii)     any one from:

•        greater sensitivity / precision       do not accept more reliable (negates mark)

•        could link to a computer for (automatic) data analysis

•        could take more frequent readings

•        reduces instrument reading error       accept more accurate       do not accept easier to use on its own

1

(b)     (i)      acts as a controlaccept to be able to make a comparisonaccept to see the differencedo not accept ‘to make it a fair test’ OWTTE on its own

1

(ii)     (plastic) foam and aluminium foil1

(iii)     (aluminium) foil is a poor absorber of thermal radiationaccept heat / infra red for thermal radiation

1

or (aluminium) foil is a (good) reflector of thermal radiationdo not accept ‘reflects sunlight’ on its own

         (plastic) foam traps air which is a (good) insulatoraccept (plastic) foam is a poor conductor / (good) insulatordo not accept ‘the material’ is a good insulator / poor conductor

1

(c)     particles vibrate with a bigger / stronger amplitude / faster / with more(kinetic) energy

accept particles vibrate moredo not accept start to vibrate only

1

energy transferred by collisions with other particlesdo not accept answers in terms offree/mobile electrons

1[9]

 

 

M33.          (a)     any three from:ignore reference to skewer

•        (air) particles / molecules / atoms gain energy

•        (air) particles / molecules / atoms move fasterdo not accept move moredo not accept move with a bigger amplitude / vibrate more

•        (air) particles / molecules / atoms move apart

•        air expandsdo not accept particles expand

•        air becomes less dense

•        warm / hot air risesdo not accept heat risesif credit is to be given for answers in terms of particles it must be clear they are air particles not gas particles

3

(b)     conductionaccept conductor

1

(c)     any one from:

•        temperature of the potatodo not accept heat for temperature

•        temperature of the surroundings / room / surface / atmosphereaccept how hot the potato / room is

•        size / mass / weight / volume of the potato

•        shape of the potato

•        surface area of the potatopotato cut open insufficient

•        nature of the surface of the potato

•        type of surface it is placed on

•        in a draught

•        type of potato

•        whether the skewers are left in or taken out1

(d)     (foil) reflects heat (back towards potato)reduces heat loss is insufficientdo not accept reflects hot air

          or (foil) is a poor emitter (of heat radiation)accept reduces / stops heat loss by radiationdo not accept heat is trapped

1[6]

 

 

M34.          (a)     (i)      makes it warmer / raises the temperatureaccept produces convection (current)accept makes it less dense

1

(ii)     reduced or slows down1

(b)     (i)      electrical energy (to run the pump) must be paid foraccept electricity for electrical energyaccept electricity is needed for the pumpaccept it uses electricityaccept because of the pump

1

(ii)     more useful (heat) energy is transferred into the house than the energyused to operate the pump

         or reduced cost of heating the house is greater than the cost of running the (electrical) pump

         or costs little to run compared to the savings madeaccept for 1 markreduces energy billsor reduced fuel costs / heating costs owttedo not accept it’s cheap

2[5]

 

 

M35.          (a)     £15allow 1 mark for use of 125 (kWh)allow 1 mark for an answer 1500allow both marks for 1500 pence / p

allow 1 mark for correct calculation of annual cost for either freezer (£27 and £42)

2

(b)     £45

          or their (a) × 3allow 1 mark for correct use of 3allow 1 mark for 12 – 9 = 3

2

(c)     any two from:the marks are for the explanation

          yes plus explanation

•        less electricity / energy needed / usedaccept less energy wasted

•        less (fossil) fuels burnedaccept a named fossil fueldo not accept conserving (fossil) fuels

•        less polluting gases emittedaccept a named polluting gas / greenhouse gases / carbon emissions / reduce global warmingaccept an answer in terms of nuclear fueleg    less nuclear fuel required (1)       less nuclear waste (1)

2

          or no plus explanation

•        old freezer must be disposed of

•        hazardous chemicals inside freezeraccept CFC gases

•        (lot of) energy used in producing new freezer[6]

 

 

M36.          (a)     (i)      small proportion of energy / power is wastedaccept little / less energy / power / heat is wasteddo not accept it wastes no energy / power

         or transfers most / more / a lot of energy power usefully

1

(ii)     it decreases the current / uses low current

         or it increases the voltage / potential differenceaccept pd for potential difference

1

         or uses high voltage / potential difference

         smaller the current the smaller the energy lossaccept power / heat for energy

1

(b)     (i)      as a controlaccept to make a comparisondo not accept fair test on its own

1

(ii)     so people know how much data the link was based onaccept idea that larger numbers are better

         or

         people can judge the significance / reliability of the linkdo not accept significance / reliability on its ownignore reference to accuracy

1

(iii)     other possible factors may be responsible1

         or have not been investigated

         named factor eg environment / genetic1

(iv)    first box ticked plus reasonacceptable reason such as so people know there may be a risk as soon as possible / so that other scientists can use findings

         or second box plus reasonacceptable reason such as no point to worry / confuse / panic people (until the research has been confirmed)accept idea that it may lead to wrong advicedo not accept in case they are wrong

1

[8]

 

 

M37.          (a)     (i)      0.6accept 60 %allow 1 mark for useful energy = 480answer 0.6 with any unit or 60 gains 1 mark only

2

(ii)     transferred to surroundingsaccept goes into the airaccept heats the surroundings upaccept gets spread outaccept transferred into heat (only)do not accept wasted / lost unless qualifieddestroyed negates marktransferred into light / sound negates mark

1

(b)     (i)      1.75allow 1 mark for converting to kWanswers of 0.7, 0.525, 0.35, 0.875, 1.05, 5.25 gains 1 markanswers of 1750 or 17.5 gains 1 mark

2

(ii)     21p or £0.21 or their (b)(i) × 121

(c)     any two from:

•        (more) electricity needs to be generated(more) electricity is being used

•        (more) power stations needed

•        (more) fossil fuels burntaccept named fossil fuel

•        (more) pollutant gases emittedaccept named gasaccept harmful for pollutantaccept greenhouse gasesaccept atmospheric pollution

accept answer in terms of any form of electricity generation and an associated environmental problem

2[8]

 

 

M38.          (a)     1/25 or 1:25 or 0.04

accept 4 % or  or 1 in 25 for both marks

 allow 1 mark for total of 375allow 1 mark for a clearly correct method using a clearly incorrect totaldo not accept 1:26

2

(b)     (i)      Bdo not credit reason if B is not chosen

1

         (only) burning fossil fuels produces carbondioxide / carbon (emissions)or nuclear fuels don’t produce carbon dioxide

insufficient – smallest amount of fossil fuelsaccept less carbon dioxide

1

(ii)     accept anything reasonable eg

         increased level of insulation

         use energy efficient light bulbs

         do not leave appliances on standby

         switch thermostats down (1°C)

         generate own electricity

         install solar panelsaccept insulateaccept specific examples eg loft

1

(c)     (i)      any three from:

•        no power output until wind speed exceeds 4m/s

•        output rises rapidly after 4m/s

•        output begins to level out / rises less rapidly at /after 13m/s

•        output peaks at 21 / 22m/s

•        output constant between 21 / 22 and 25 / 26 m/s

•        output falls (rapidly) after 25 / 26m/saccept for 1 mark goes up then comes down

3

(ii)     any one from:

•        unreliable energy source

•        dilute energy source

•        take up too much landaccept wind does not always blowaccept need thousands / lots of turbinesignore reference to visual / noise pollutionignore reference to kill birds

1[9]