energy transfers, gpe, ke & efficiency · 2018. 5. 25. · 3(c)(ii) after falling 50 m / when...

Energy Transfers, GPE, KE & Efficiency

Mark Scheme 1

Level Edexcel

Subject Physics

Exam Board GCSE(9-1)

Topic Conservation of Energy

Sub Topic Energy Transfers, GPE, KE & Efficiency

Booklet Mark Scheme 1

60 minutes

/50

/100

Time Allowed:

Score:

Percentage:

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Question Number

Answer Acceptable answers Mark

1(a)(i) electrical electric (1)

Question Number


1(a)(ii) chemical (1)

Question Number


1(b)(i) 20 (J) 200 – 180 (even if calculated value from this is incorrect)

(1)

Question Number


1(b)(ii) (changed to) {thermal energy / heat}

dissipated

(lost) to {surroundings / motor / air / atmosphere}

sound / noise

reject if kinetic, light or chemical is mentioned

(1)


Question Number


1(b)(iii)

180 × 100 (1) 200

90 (%) (1)

award full marks for correct answer with no working

180 200

0.9, 9/10

Or [100 – (20/200)]

% not needed but if a unit is given then maximum score is 1

(2)

Question Number


1(c)(i) D dark : rough (1)

Question Number


1(c)(ii) C the container is losing thermal energy at the same rate it is absorbing it

Heat for thermal Same amount in same time for same rate

(1)

Total for Question 1 = 8 marks


Question Number


2(a) kinetic (energy) Movement (energy) KE

(1)

Question Number


2(b) substitution: 0.6 x 20 (1)

evaluation 12 (1)

J (1)

give 2 marks for correct answer no working

unit is an independent mark joules, Nm, kgm2/s2 , Ws

(3)

Question Number


2(c) (1)

substitution: 0.5 x 18

evaluation 9.0 (1) 9

give full marks for correct answer no working (2)


Question Number

Indicative Content Mark

QWCQWC * ) a description including some of the following points:

• chemical to kinetic while in his hand• kinetic (gradually) to potential while rising / from 0-10 m• eventually all potential at 10 m with a little thermal

(heat) energy• some mention of conservation of energy• potential (gradually) to kinetic as falls / 10 m-0• with a little more thermal (heat) energy• at 0 m sound energy• at 0 m thermal (heat) energy (6)

Level 0 No rewardable content 1 1 - 2 • a limited description which identifies a change in one relevant

type energy or a transfer of energy from one form to anothere.g. kinetic energy increases OR kinetic energy changes tosound.

• the answer communicates ideas using simple language and useslimited scientific terminology

• spelling, punctuation and grammar are used with limitedaccuracy

2 3 - 4 • a simple description giving detail of a relevant energychange/transfer e.g. kinetic energy changes into potential energyas it moves upwards OR kinetic energy increases as it falls.

• the answer communicates ideas showing some evidence of clarityand organisation and uses scientific terminology appropriately

• spelling, punctuation and grammar are used with some accuracy3 5 - 6 • a detailed description of a sequence of relevant energy changes

/transfers e.g. kinetic energy is transferred into potential energyas it rises. This then changes back into kinetic energy as it fallsback down.

• the answer communicates ideas clearly and coherently uses arange of scientific terminology accurately

• spelling, punctuation and grammar are used with few errors


Question Number


3(a) C when the bungee cord is stretched the most (1)

Question Number


3(b) A 600 kg m/s (1)

Question Number


3(c)(i) Substitution: (1) 60 x 10 x 50 or 600 x 50

Evaluation: (1) 30 000

Unit: (1) J / Nm

give two marks for correct answer no working

j / joule 30 kJ for full marks

(3)

Question Number


3(c)(ii) After falling 50 m / when the cord becomes straight/when cord starts to stretch

tension starting to increase

at terminal velocity ignore maximum velocity/speed

(1)

Question Number


3(c)(iii) An explanation linking any two of

not all GPE is transferred to KE (1)

some {of the GPE transfers to thermal energy /work is done} (1)

due to drag (1)

not all GPE goes to KE

maximum energy is same (value) as GPE before falling /speed does not reach the speed at which he should fall

some lost as heat/sound (of rope or movement through air)

(air) resistance / friction

ignore wind (2)


Question Number


4(a) elastic potential energy (1)

Question Number


4(b)(i) 0.3(J) (1) 0.5-0.2 (J) (1)

Question Number


4(b)(ii) substitution (1) 0.2÷0.5

evaluation (1) 0.4 / 40(%) / 2/5

Give full marks for correct answer with no working

(2)

Question Number


4(b)(iii) Any two of the following

• thermal/heat (1)

• (idea that energy is)dissipated/spreads out (1)

• to the surroundings (1)

Ignore transferred to

Atmosphere/air

Accept makes surroundings warmer (2) Ignore lost (2)


Question Number

Indicative content Mark

QWC *4(c) A description including some of the following points

Forms of energy • gravitational potential energy• kinetic energy• elastic potential energy• heat(thermal) and sound

Location of energy • gravitational potential energy of mass as it rises• kinetic energy of mass as it moves• Elastic potential energy stored in spring• Heat/sound dissipated to surroundings

Linked ideas • As the pendulum falls, gravitational potential energy

changes to kinetic energy.• the kinetic energy from the pendulum ends up as heat,

warming the surroundings.• the elastic potential energy in the clockspring becomes

kinetic energy of the pendulum to keep the pendulumswinging. (6)

Level 0 no rewardable material 1-11 • a limited description including the name of one form of energy that

is involved in the pendulum swing eg. the pendulum has kineticenergy.


• spelling, punctuation and grammar are used with limited accuracy22 3- • a simple description of the pendulum swing indicating where the

energy can be found OR a simple transfer eg. When the pendulumis moving it has kinetic energy / the pendulum is high at the side ofthe swing so it has gravitational potential energy / As thependulum swings it loses heat to the air / kinetic energy changes topotential energy / KE to PE.


• spelling, punctuation and grammar are used with some accuracy3 5 - 6 • a detailed description of an energy transfer indicating where the

energy can be found and where the transfer takes place eg. as thependulum swings to and fro, gravitational potential energy changesto kinetic energy / kinetic energy is dissipated as heat and sound tothe surroundings




Question Number


5(a) A (1)

Question Number


5(b)(i) both points correctly plotted (1) allow +/- half square (1)

Question Number


5(b)(ii) smooth curve (1) ( does not need to go through all points i.e. can miss out top section)

allow slight discontinuities/double lines/ thick lines

NOT dot to dot /two straight lines (1)

Question Number


5(b)(iii) temperature from 34 °C to 39 °C inclusive (1) (1)

Question Number


5(b)(iv) 21(°C) (1) 22( °C) /23(°C ) (1)

Question Number


5(c)(i) it/black is a good absorber of heat /energy/radiation/IR (1) i.e. it absorbs/takes in moreinfrared/IR

allow it/black absorbs/takes in heat

ignore attracts/emitter/conductor NOT (so it ) cools down quickly (1)


Question Number


5(c)(ii) substitution (1) 9000 ÷ 20

evaluation (1)

450 (W)

ignore powers of 10 until evaluation

e.g. 90 ÷ 2 gains 1 mark45 gains 1 mark

give full marks for correct answer, no working (2)

Question Number


5(c)(iii) substitution (1)

9000 ÷ 18 000 ( x 100% )

evaluation (1)

50 (%)


e.g. 90 000 ÷ 1800 gains 1 mark5 gains 1 mark

0.5 or ½ or half gains both marks

give full marks for correct answer, no working

(2)



Mark Scheme 2

Level Edexcel

Subject Physics





54 minutes

/45

/100

Time Allowed:

Score:

Percentage:



Question Number


1(a) D (1)

Question Number


1(b) substitution (1) 0.5 × 6.0

evaluation (1) 3

unit (1) W / watts

give (2) for correct answer, no working

0.003 kW (3) 3 kW (2)

J/s, VA Accept kW for unit with incorrect or no numerical answer

(3)

Question Number


1(c)(i) 150 (J) 200 – 50 (J) 200 minus 50 (J) (1)

Question Number


1(c)(ii) substitution (1) 50 ÷ 200 (x 100%)

evaluation (1) 25 (%) 0.25, 1/4

give (2) marks for correct answer, no working (2)

Question Number


1(d) (black) is a good {(thermal) emitter / radiator}

to keep the motor cool / eq ignore absorbing / conducting / insulating heat (1)


Question Number


2(ai) (Bow and arrow:) kinetic (1)

(Electric kettle:) heat (thermal) (1)

(Microphone: ) sound (1)

Heat/thermal (3)

Question Number


2(a)(ii) Any one from (transferred into) {thermal/heat/sound}(energy) (1)

(Energy) is dissipated (1)

Do not accept light energy or it disappears

goes into surroundings/air

(energy) is wasted/lost

(1)

Question Number


2(b)(i) 12 (J) Ignore any unit given by candidate.

20 - 8 (J) (1)

Question Number


2(b)(ii) An explanation linking any two of

• (For the) same amount of{electrical/supplied}(energy/power) (1)

• (CFL/it) has a greateroutput (of light energy) (1)

• (CFL/it) wastes less(electrical energy) (1)

Same input (energy)

gives out/produces more {light/useful} (energy) Do not accept more energy is used in the (CFL/it) Ignore brightness.

(CFL/it) produces less thermal/heat (energy)

Accept explanations using data from the energy transfer diagrams as comparisons eg (CFL/it) is four times as efficient gains both marks

(2)


Question Number


2(c) An explanation linking

• dissipating heat (1)

• at same (rate)/as quicklyas energy is beingsupplied (1)

{gives out/radiates/conducts/ convects /loses /produces} {heat/thermal/ energy}

gives out as much energy/power as it takes in(each second) Gains both marks

If no other marks scored: There is a constant current/ steady flow of energy into the heater gains one mark

Ignore refs to thermostat

(2)



Question Number


3 (ai) A line connecting a train part with a useful energy transfer as shown below (1)

Train part useful energy transfer

Lines need not be straight

Ignore any arrow heads drawn

Note: if more than one line is drawn from a train part then zero mark for that train part.

(3)

Question Number


3 (aii) (transfer of energy to) thermal (1)

heat/sound (1)

Question Number


3 (bi) 1400 – 1300 (= 100) (kJ) (1)

(1)

Question Number


3 (bii) Substitution (1) 1300 / 1400 x 100

Evaluation (1) 93(%) or 0.93 A value which rounds to 93(%)

or 0.93

Correct answer with no working scores 2 marks

(2)

chemical to electrical

electrical to kinetic

kinetic to chemical

kinetic to electrical

diesel engine

generator

motor

chemical to kinetic


Question Number


3 (c) Any one from

black is a good thermal radiator (1)

(helps to) prevent motors overheating (1)

(good) emitter

(helps to) remove wasted energy/ heat (from the motor)

(1)


Question Number


4(b)(i)

(ii)

6%

comparing reflected amount for water with any one of the others (1)

100 - 94

saying one {named material (on the graph) is/all materials (on the graph) are} solid

(1)

(1)

Question Number


4(c)(i) An explanation to include the following

• more thermal (heat) energyis absorbed (1)

• because water (liquid)absorbs more than ice (solid)(1)

more radiation is absorbed

because water (liquid) reflects less than ice (solid)

because less ice surface to reflect

because more water surface to absorb (2)

Question Number


4(c)(ii) its temperature rises gets hotter

water level increases/gets higher

Ignore ‘{water/it} {increases/rises}’

Reject toxicity (1)

Question Number


4(a) A (1)


Question Number


QWC *4(d )

A description including some of the following

• solar / heat / light• photosynthesis• chemical / fossil fuel• burning• thermal• in steam• kinetic• in turbine• electrical• in generator (6)

Level 0 no rewardable material

1 -2 • a limited description which identifies an energy in an appropriate placee.g. thermal energy in the boilerOR e.g. the (same) energy flows from the boiler to the turbine

• the answer communicates ideas using simple language and uses limitedscientific terminology

• spelling, punctuation and grammar are used with limited accuracy2 -4 • a simple description which includes details of a relevant energy transfer

e.g. (steam causing) the turbine to rotate turns the coil in the generatortransferring kinetic energy into electrical energy

• the answer communicates ideas showing some evidence of clarity andorganisation and uses scientific terminology appropriately

• spelling, punctuation and grammar are used with some accuracy

3 5 - 6 • a detailed description to includes details of a sequence of transfers e.g.chemical energy stored in the coal is transferred in the boiler to thermal energy producing steam. The steam turns the turbine which turns the coil.

• the answer communicates ideas clearly and coherently uses a range ofscientific terminology accurately



Question Number


5(a) C (1)

Question Number


5(b)(i) Any two from the following points

• cover box with transparentmaterial (1)

• use of reflector (1)

• method to increase energysupplied (1)

• method to reduce energy loss(1)

• paint (box) black/dull/matt(1)

use glass box

mirror / foil

{angle to sun} / {warmer place}/lens

use insulating box / wooden box / lagging

Ignore answers to do with hosepipe (2)

Question Number


5(b)(ii) An explanation linking the following points

• pipe / water absorbs heat (1)

• pipe radiates heat (1)

• radiation (rate) increaseswith temperature(1)

• (at constant temperature)absorption rate = radiationrate (1)

accept takes in for absorbs

accept emits for radiates

If no other marks given accept output = input or water boils for 1 mark (3)


Question Number


5(c) 4000 (1)

(4000)/200 (1) 20 (W)


accept for 1 mark 4000 10000/200 6000/200 16000/200

(2)



Mark Scheme 3

Level Edexcel

Subject Physics





56 minutes

/46

/100

Time Allowed:

Score:

Percentage:



Question Number


1(a)(i)

drill kinetic energy radio sound torch light

More than one line to or from a box gets no mark for that box.

(3)

Question Number


1(a)(ii) heat/thermal/internal (1)

Question Number


1(b)(i) 300 / 2500-2200 (J) Accept correct working with wrong answer

(1)

Question Number


1(b)(ii) chemical to heat/thermal/internal

(1)

Question Number


1(b)(iii) An explanation linking any two of the following:

• Kettle insulated / beaker isnot insulated (1)

• kettle loses/wastes lessheat or energy ORA (1)

• element inside kettle /bunsen or flame open (tosurroundings) (1)

Kettle is plastic/more closed/has a lid/keeps in heat or energy ORA

kettle is more efficient ORA

Kettle keeps in more energy = 2 marks ORA IGNORE references to gas/electricity or light/sound energy or speed of boiling

(2)


Question Number


2(a)(i) A (1)

Question Number


2(a)(ii) An explanation linking the following:

• {energy / heat / radiation}is lost (1)

•

•

(heat lost) = heat gained /absorbed (1)rate (of heat loss) = rate(of heat gained) (1)

given out /output for ‘is lost’

power lost = power gained =3 description of dynamic equilibrium =3

Ignore references to boiling water

(3)

Question Number


2(b)(i) D (1)

Question Number


2(b)(ii) substitution (1)

5 000 000 / 21 700

evaluation (1)

230 W

Ignore powers of 10 until evaluation

230.4 W

Give full marks for correct answer, no working 2.3 x any other power of 10 = 1 mark

(2)

Question Number


2(b)(iii) substitution (1)

5 x 100 / 25

evaluation (1)

20(%) 0.2, 1/5

Give full marks for correct answer, no working 2 x any other power of 10 = 1 mark e.g. 200, 1/500

(2)


Question number

Answer Mark

3(a)(i) (Carried by) electromagnetic wave

(1)

Question number

Answer Mark

3(a)(ii) As chemical energy in the battery

(1)

Question number

Answer Additional guidance Mark

3(a)(iii) Calculation of area (1) 7 × 11

Substitution (1) 77 × 0.12

Answer (1) 9.2 (J)

77

ecf area

award full marks for correct numerical answer without working (3)

Question number


3(b) An explanation that combines identification – understanding (1 mark) and reasoning/justification – understanding (1 mark):

• the heating effect forthe oven and the phonedepends on their power(1)

• and since the power ofan oven is much greaterthan the power of aphone, the ovenproduces a greaterheating effect (1)

allow not the same wavelength/microwaves cover a range in wavelengths

(2)


Question number


4(a) rearrangement (1)

m = fa

substitution and conversion (1)

1.83m =

1870

answer and rounding to 3 s.f. (1) 1020 (kg)

maximum 2 marks if kN not converted to N

award full marks for correct numerical answer without working

(3)

Question number


4(b) ( −v u)= a

t(1)rearrangement of

v = u + at

substitution (1) v = 0 + 1.83 × 16

answer (1) 29.3 (m/s)

award full marks for correct numerical answer without working

(3)


Level Mark Descriptor

0 No awardable content.

1 1–2 • Interpretation and evaluation of the information attempted butwill be limited with a focus on mainly just one variable.Demonstrates limited synthesis of understanding. (AO3)

• The description attempts to link and apply knowledge andunderstanding of scientific ideas, flawed or simplisticconnections made between elements in the context of thequestion. (AO2)

2 3–4 • Interpretation and evaluation of the information on bothvariables, synthesising mostly relevant understanding. (AO3)

• The description is mostly supported through linkage andapplication of knowledge and understanding of scientific ideas,some logical connections made between elements in thecontext of the question. (AO2)

Question number


*4(c) Answers will be credited according to candidate's deployment of knowledge and understanding of the material in relation to the qualities and skills outlined in the generic mark scheme.

The indicative content below is not prescriptive and candidates are not required to include all the material which is indicated as relevant. Additional content included in the response must be scientific and relevant.

AO2

• fuel forms a store of chemical (potential) energy• chemical energy is transferred to kinetic energy and

thermal energy when the car moves• kinetic energy transferred to thermal energy as the car

slows down

AO3 • during X, kinetic energy increases as the car’s speed

increases/car accelerates and the increase in kinetic energyis provided by the chemical energy store

• during all three sections, work is done against frictionalforces in the moving parts of the car and against the dragfrom the air

• during Y, kinetic energy stays constant when the car movesat constant speed but energy is still transferred to thermalenergy

• during Z, kinetic energy decreases as the car slows down (6)


3 5–6 • Interpretation and evaluation of the information,demonstrating throughout the skills of synthesising relevantunderstanding. (AO3)

• The description is supported throughout by linkage andapplication of knowledge and understanding of scientific ideas,logical connections made between elements in the context ofthe question. (AO2)


Question Number


5 (a)(i) 2.5 (m) Allow answers between (and including) 2.45 & 2.55

(1)

Question Number


5 (a)(ii) 0.7 (s) Allow answers between (and including) 0.68 & 0.72

(1)

Question Number


5 (a)(iii)

line:

same shape as original (1)

peak at 1.9 m (1)

time taken < 0.7 s (1)

Ignore any part of the graph after the peak

(3)

Question Number


5 (a)(iv) An explanation linking:

energy lost (1)

in collision with ground / air resistance (1)

Inelastic collision worth (2)

as sound or heat (2)


Question Number


5 (b)(i) shown using data Any two from kinetic energy before = 12.5 + 0 (=12.5) (1) kinetic energy after = 4.5 + 8 (=12.5) (1)

Kinetic energy is the same before and after the collision (1)

Kinetic energy is conserved/no energy lost (2)

Question Number


5 (b)(ii) cyclotron (1) named particle accelerator accept CERN (1)

Total mark for question 4 = 10



Mark Scheme 4

Level Edexcel

Subject Physics





45 minutes

/37

/100

Time Allowed:

Score:

Percentage:



Question Number


1(a) Any one of the following points

• unreliability (1)e.g. wind does not alwaysblow / wind speed may betoo high/too low

• pollution (1)e.g. noise from windturbines / wind turbinesspoil the view

Ignore general references to weather ignore economic arguments

the wind is unreliable only works when it is windy wind turbines can only use a (small) range of wind speeds

visual pollution (1)

Question Number


1(b)(i)

transposition (1) current = power ÷ voltage

substitution (1) 322 000 000 ÷ 132 000

evaluation (1) 2440 (A)

Transposition and substitution may be in either order Transposition may be implied by correct figures

I = P ÷ V

Ignore powers of ten until final answer i.e. give 2 marks for 322 ÷ 132

2439 (A) 2439.39….(A) 2.44 kA

give full marks for correct answer, no working give 2 marks for a power of 10 error, no working e.g. 2.44 (A) (3)

Question Number


1(b)(ii) • calculation to find additionalpower generated e.g.539 – 322 = 217 (MW) (1)

• 2.9 (MW) (1)

217 without working

2.893 (MW)



Question Number


QWC *1(c) A discussion to include some of the following points

Social factors / economic factors • people may not like it (NIMBY) / pressure groups• cost arguments

Environmental factors • spoiled view / risk of birdstrike• space for extra infrastructure eg. access roads / substations

Associated hazards • danger from higher voltage• dangers from construction work in mountainous area• danger to maintenance crew from working at greater height

Energy efficiency arguments • higher voltage leads to lower current• lower current means reduced heat losses• higher voltage means / lower current / can transmit energy

further• reduced heat loss means improved efficiency

Logical use of data • taller pylons can be seen from further away• net reduction in number of pylons / need to remove old ones• stronger materials needed for pylons / cables• need for new transformers

Appropriate calculations • 1000 - 600 = 400 fewer pylons (approx)• current reduced by a factor of 132/400 (0.33) (6)



1 1-2 • a limited discussion of the plan to replace the power transmission lines(or upgrade the wind farm) including two or more points, advantageous (A) or disadvantageous (D), which may appear as a list e.g.

(A+D) is more efficient; is expensive OR (A+A) uses fewer pylons; current is lower OR (D+D) would spoil the view; high voltage is dangerous • the answer communicates ideas using simple language and uses limited

scientific terminology • spelling, punctuation and grammar are used with limited accuracy

2 3-4 • a simple discussion of the plan to replace the power transmission linesincluding two or more statements, advantageous (A) or disadvantageous (D), at least one of which links ideas e.g. (A) higher voltage leads to lower current + (D) if old pylons are

removed they will go to waste OR (A) using higher voltage means energy can be transmitted further

+ (A) wasting less energy saves money OR (D) new pylons spoil the view more because they are taller + (D)

danger to maintenance crew from working at greater height • the answer communicates ideas showing some evidence of clarity and

organisation and uses scientific terminology appropriately • spelling, punctuation and grammar are used with some accuracy

3 5 - 6 • a detailed discussion of the plan to replace the power transmissionline, including an advantage (A) AND a disadvantage (D) both containing linked ideas, at least one of which shows use of the data e.g.

(A) Increasing the voltage to 400 kV leads to a reduction in the current(needed to transmit the same power) + (D) higher voltages will mean that they need new transformers

OR (A) it will be more efficient because less energy is wasted + (D) even though there will be 400 fewer pylons they will be taller and can be seen from further away

• the answer communicates ideas clearly and coherently uses a rangeof scientific terminology accurately



Question Number


2(ai) Model A because

Model A (can produce up to )7200kWh per year (at 13mph) / will produce 6000 kWh (with given wind speed). (1)

Model B produces less than 6000kWh per year at 13mph /requires wind speed of more than 13mph to produce 6000kWh

(1)

Question Number


2(aii) Substitution (1) 0.14 x 6000

Evaluation (1) (£)840

Allow incorrect conversion of p to £ such as 0.014 x 6000 for 1 mark only

84 000 p

correct answer with no working shown gains both marks

(2)

Question Number


2(aiii) Divide the installation cost by the annual saving (to find the time in years) (1)

£840 for annual saving (1)

Question Number


2(aiv) A suggestion linking

(energy saving lamps) would not transfer so much thermal energy (1)

he may have to use additional heating / lights (which would cost money to run/ purchase) (1)

not get hot / produce so much heat

reverse argument such as insufficient heat for chicks to thrive

(Ignore references to light output.)

(2)


Question Number


QWC *2(b) A discussion including some of the following points

• Both HEP and Solar power are renewable• Both HEP and Solar power would save fossil fuels• HEP only possible in some locations• HEP requires reservoirs and damming of rivers•

•

This can damage environment /takes a lot of land out ofuseEnergy from solar power installation is currently muchless than energy from fossil fuel powered station

• Solar power only suitable in certain locations• Solar power reliability dependent on constant sunshine• Neither of them cause atmospheric pollution

(6)

Level 0 No rewardable content 1 1 - 2 • a limited description such as at least one relevant detail of each

resource eg: Solar power doesn't give off atmospheric pollution.HEP generates more power than solar power.



2 3 - 4 • a simple discussion such as one which gives comparisonsbetween the two or at least an advantage and disadvantage ofboth. eg: HEP does not use fossil fuels but it can damage theenvironment where is it located. Solar power will never run outbut it requires lots of light/land.

• the answer communicates ideas showing some evidence ofclarity and organisation and uses scientific terminologyappropriately

• spelling, punctuation and grammar are used with some accuracy3 5 - 6 • a detailed comparison such as one which relates advantages and

disadvantages of both HEP and solar power to a particularsituation for possible large scale use e.g.: Solar power uses arenewable energy source but it currently does not produce asmuch energy as fossil fuel station where there is little sunlight.HEP can produce a lot more energy where there are hills andwater but only possible in certain geographical locations.




Question number


3(a) An answer that combines the following points of understanding to provide a logical description:

• measurement of timebetween(or at) twopositions usingsuitable timingequipment (1)

• measurement ofsuitable distancealong the runwaywith metre rule (1)

• measurement of verticalheight to starting position(1)

• repeats AND averagesAND use of a correctequation (1)

allow

stopwatch, light gates

minimum is 0.5  m metal tape measure

average speed = distance/time OR average speed = (speed at A − speed at B)/2

(4)


Question number


3(b)(i) Substitution of correct data from graph and mass conversion (1)

0.5 × 0.65 × (0.61)2

Answer (1)

0.12 (J)

maximum of 1 mark if mass in g used

allow tolerance of ±0.2 for speed

(2)

Question number


3(b)(ii) • Tangent to the graph ath = 0.1 (1)

• Answer in the region 3.5 to3.6

either seen on graph or suitable pairs of values of Δv and Δh

(2)


Question number

Answer Mark

3(b)(iii) An answer that combines points of interpretation/evaluation to provide a logical description:

• for each change in height, as the height increases thespeed of the trolley increases

• the greatest change in speed is between the change inheight from 0.04  m to 0.9  m

(2)

Question number


3(c) An answer that combines the following points to provide a logical description of the plan/method/experiment:

• identifies controlvariables (1)

• uses at least 3 differentsurfaces (1)

• calculates average speedfor each surface andrepeats (1)

constant height, constant slope, constant starting points and same length of surface

(3)


Energy Sources Mark Scheme 1

Level Edexcel

Subject Physics



Sub Topic Energy Sources


53 minutes

/44

/100

Time Allowed:

Score:

Percentage:



Question

Number


1(a) A transverse and electromagnetic (1)

Question Number


1(b)

(1)

(3)

(1)

Evaluation 171.5

Substitution (34.3/171.5) x 100

Evaluation 20 (%) (1)

award full marks for correct answer with no working

34.3 x 5

[34.3 /(34.3 x 5)] x 100 [34.3 /(34.3 x 5)] [34.3 /171.5]

Allow 0.2 or 1/5 for 3 marks

Question Number


1(c) rate of {energy/heat} (from the Sun){absorbed/taken in} (1)

equals rate of {energy/heat}

{radiated/emitted/given out} (1)

Allow ‘energy in = energy out’ for 1 mark

‘power in = power out’ for 2 marks

(2)

Question

Number


1(d) Any two suggestions from:

reflection (from external

connections/plastic cover)(1)

absorption by {external connection/ plastic cover/back plate} (1)

transmission (through back plate) (1)

Not all energy absorbed by silicon layer/absorbed by wrong parts

(2)



Question Number


2(a) Any one of the following points

• unreliability (1)e.g. wind does not alwaysblow / wind speed may betoo high/too low

• pollution (1)e.g. noise from windturbines / wind turbinesspoil the view

Ignore general references to weather ignore economic arguments

the wind is unreliable only works when it is windy wind turbines can only use a (small) range of wind speeds

visual pollution (1)

Question Number


2(b)(i)

transposition (1) current = power ÷ voltage

substitution (1) 322 000 000 ÷ 132 000

evaluation (1) 2440 (A)

Transposition and substitution may be in either order Transposition may be implied by correct figures

I = P ÷ V

Ignore powers of ten until final answer i.e. give 2 marks for 322 ÷ 132

2439 (A) 2439.39….(A) 2.44 kA

give full marks for correct answer, no working give 2 marks for a power of 10 error, no working e.g. 2.44 (A) (3)

Question Number


2(b)(ii) • calculation to find additionalpower generated e.g.539 – 322 = 217 (MW) (1)

• 2.9 (MW) (1)

217 without working

2.893 (MW)



Question Number


QWC *2(c) A discussion to include some of the following points

Social factors / economic factors • people may not like it (NIMBY) / pressure groups• cost arguments

Environmental factors • spoiled view / risk of birdstrike• space for extra infrastructure eg. access roads / substations

Associated hazards • danger from higher voltage• dangers from construction work in mountainous area• danger to maintenance crew from working at greater height

Energy efficiency arguments • higher voltage leads to lower current• lower current means reduced heat losses• higher voltage means / lower current / can transmit energy

further• reduced heat loss means improved efficiency

Logical use of data • taller pylons can be seen from further away• net reduction in number of pylons / need to remove old ones• stronger materials needed for pylons / cables• need for new transformers

Appropriate calculations • 1000 - 600 = 400 fewer pylons (approx)• current reduced by a factor of 132/400 (0.33) (6)



1 1- • a limited discussion of the plan to replace the power transmission lines(or upgrade the wind farm) including two or more points, advantageous (A) or disadvantageous (D), which may appear as a list e.g.

(A+D) is more efficient; is expensive OR (A+A) uses fewer pylons; current is lower OR (D+D) would spoil the view; high voltage is dangerous • the answer communicates ideas using simple language and uses limited

scientific terminology • spelling, punctuation and grammar are used with limited accuracy

2 3- • a simple discussion of the plan to replace the power transmission linesincluding two or more statements, advantageous (A) or disadvantageous (D), at least one of which links ideas e.g. (A) higher voltage leads to lower current + (D) if old pylons are

removed they will go to waste OR (A) using higher voltage means energy can be transmitted further

+ (A) wasting less e ergy saves money OR (D) new pylons spoil the view more because they are taller + (D)

danger to maintenance crew from working at greater height • the answer communicates ideas showing some evidence of clarity and

organisation and uses scientific terminology appropriately • spelling, punctuation and grammar are used with some accuracy

3 5 - 6 • a detailed discussion of the plan to replace the power transmissionline, including an advantage (A) AND a disadvantage (D) both containing linked ideas, at least one of which shows use of the data e.e.

(A)A) creasing the voltage to 400 kV leads to a reduction in the current(needed to transmit the same power) + (D) higher voltages will mean that they need new transformers

OR (A) it will be more efficient because less energy is wasted + (D) even though there will be 400 fewer pylons they will be taller and can be seen from further away

• the answer communicates ideas clearly and coherently uses a rangeof scientific terminology accurately



Question Number


3(a) B(1)

Question Number


3(b)(i) an explanation linking three of the following

• (waves cause) float to move(up and down)(1)

• (this causes) magnet tomove (in and out of coil)(1)

• (hence) magnetic field (ofmagnet) (1)

• cuts across/links/ interactswire in coil (1)

• inducing/generatingpotential difference acrossends of coil (1)

magnet moves (in the coil)

Allow{current/voltage/volts/amps} induced/generated in coil

(3)

Question Number


3(b)(ii) a description including two of the following

• increase the number ofturns on the coil (1)

• use a more powerfulmagnet (1)

• use full scale device (1)

more coils (of wire) ignore bigger coil

stronger/more magnets Ignore bigger magnet

Allow idea of more/bigger/ faster waves (2)


Question Number


QWC *3(c) A discussion linking some of the following Advantages of tidal power

• renewable energy source• reduction in greenhouse gases/atmospheric pollution (

compared to fossil fuel)• reduces reliance on fossil fuels• conserves stocks of fossil fuels• predictable source of energy• regular/reliable supply of energy• barrages at different areas would give energy supply at

different timesDisadvantages of tidal power

• does not give continuous supply of energy• destruction of plant/animal/bird habitats• problems with passage of ships• affects migration of fish• high capital cost /very long payback time• pollution caused from producing /transporting building

materials • visual pollutionThis list is not exhaustive. Give credit for other plausiblesuggestions (6)

Level 0 No rewardable material 1 1- • there is limited discussion of the advantages or disadvantages of

tidal power ie gives one advantage OR one disadvantage of tidal power. e.g. tidal power is not available 24 hours a day/ The barrage willsave fuel for motorists going to the town on the other side ( of the estuary)


• spelling, punctuation and grammar are used with limited accuracy2 3- • there is some discussion of the advantages and disadvantages of

tidal power ie gives one advantage AND one disadvantage of tidal power e.g. an advantage of tidal power is that it uses a renewable energyresource and a disadvantage is that they damage birds’ habitats


• spelling, punctuation and grammar are used with some accuracy3 5 - 6 • there is detailed discussion of the advantages and disadvantages

of tidal power ie gives one advantage AND one disadvantage of tidal power, one of which is detailed, AND a clear link to another method e.g. tidal power stations are a good idea because they use arenewable energy resource and will help to conserve fossil fuel stocks. However, it causes problems for migrating fish




Question Number


4(ai) Model A because

Model A (can produce up to )7200kWh per year (at 13mph) / will produce 6000 kWh (with given wind speed). (1)

Model B produces less than 6000kWh per year at 13mph /requires wind speed of more than 13mph to produce 6000kWh

(1)

Question Number


4(aii) Substitution (1) 0.14 x 6000

Evaluation (1) (£)840

Allow incorrect conversion of p to £ such as 0.014 x 6000 for 1 mark only

84 000 p

correct answer with no working shown gains both marks

(2)

Question Number


4(aiii) Divide the installation cost by the annual saving (to find the time in years) (1)

£840 for annual saving (1)

Question Number


4(aiv) A suggestion linking

(energy saving lamps) would not transfer so much thermal energy (1)

he may have to use additional heating / lights (which would cost money to run/ purchase) (1)

not get hot / produce so much heat

reverse argument such as insufficient heat for chicks to thrive

(Ignore references to light output.)

(2)


Question Number


QWCQWC * ) A discussion including some of the following points

• Both HEP and Solar power are renewable• Both HEP and Solar power would save fossil fuels• HEP only possible in some locations• HEP requires reservoirs and damming of rivers•

•

This can damage environment /takes a lot of land out ofuseEnergy from solar power installation is currently muchless than energy from fossil fuel powered station

• Solar power only suitable in certain locations• Solar power reliability dependent on constant sunshine• Neither of them cause atmospheric pollution

(6)

Level 0 No rewardable content 1 1 - 2 • a limited description such as at least one relevant detail of each

resource eg: Solar power doesn't give off atmospheric pollution.HEP generates more power than solar power.



2 3 - 4 • a simple discussion such as one which gives comparisonsbetween the two or at least an advantage and disadvantage ofboth. eg: HEP does not use fossil fuels but it can damage theenvironment where is it located. Solar power will never run outbut it requires lots of light/land.

• the answer communicates ideas showing some evidence ofclarity and organisation and uses scientific terminologyappropriately

• spelling, punctuation and grammar are used with some accuracy3 5 - 6 • a detailed comparison such as one which relates advantages and

disadvantages of both HEP and solar power to a particularsituation for possible large scale use e.g.: Solar power uses arenewable energy source but it currently does not produce asmuch energy as fossil fuel station where there is little sunlight.HEP can produce a lot more energy where there are hills andwater but only possible in certain geographical locations.





Level Edexcel

Subject Physics





39 minutes

/32

/100

Time Allowed:

Score:

Percentage:



Question Number


1(a)(i) D (1)

Question Number


1(a)(ii) ampere(s), amp(s), A (1)

Question Number


1(b)(i) A description linking

magnet (1) (in/near) coil (1)

(magnet/coil) spins/moves/turns (1)

IGNORE handle turns

(3)

Question Number


1(b)(ii) Any one from the following:

Increase strength of magnet (1)

Increase number of coils/turns of wire (1)

Increase speed of rotation (1)

add another magnet / move magnets closer

turn handle/magnet/coil faster

IGNORE bigger magnet/coil/ generator / longer wire

(1)


Question Number


QWCQWC * ) A comparison including some of the following points

Non- renewable sources • coal, oil, gas and nuclear• coal, oil, gas are fossil fuels• fossil fuels will run out• fossil fuels burn and produce CO2

• fossil fuels burn to produce atmospheric pollution• CO2 contributes to global warming• are a more expensive source• Nuclear power stations do not produce CO2

• Nuclear power produces radioactive waste• Radioactive waste is dangerous and difficult to store safely

Renewable resources • Wind, waves, solar, biofuels, geothermal and hydroelectric• are a free/cheaper source• The energy source is unreliable• No (net) CO2 produced• No atmospheric pollution (except biofuels)• Waves and hydroelectric cause environmental changes• Wind farms and solar panels give visual pollution• Wind farms can be built off shore

Comparison • Fossil fuel power stations are cheaper to build than wind

farms for the same power output• Coal, oil, gas and nuclear fuel will run out, wind, waves

and sun will always be available• Fossil fuel power stations produce CO2 which may increase

global warming, renewable energy generators (windfarms) do not

• Renewable energy generators have a free/cheaper sourceof fuel

• fossil fuels have to be taken out of the ground• Nuclear power stations produce radioactive waste, which

is dangerous, none of the other energy generators do this.• Wind, waves and sun are unreliable sources of energy but

fossil and nuclear fuels are always available

(6)


Level

0 No rewardable content

1 1 - 2 • a limited statement about either renewable or non-renewable e.g.Coal is non-renewable OR renewable energy will not run out OR oilwill run out

• the answer communicates ideas using simple language and useslimited scientific terminology.

• spelling, punctuation and grammar are used with limited accuracy.2 3 - 4 • a simple comparison including 2 statements covering renewable

and non-renewable e.g. Coal is non-renewable and solar power isrenewable OR renewable energy sources will not run out and non-renewable sources do not pollute the atmosphere OR oil will runout, solar will not

• the answer communicates ideas showing some evidence of clarityand organisation and uses scientific terminology appropriately.

• spelling, punctuation and grammar are used with some accuracy.33 -6 5 • a detailed comparison including at least 3 statements with a direct

comparison between a renewable and a non-renewable source, atleast one named e.g. Renewables will not run out but non-renewables like coal will. OR Coal is non-renewable. When it isburnt carbon dioxide is produced. Wind farms do not produce anycarbon dioxide. OR Carbon dioxide is produced when coal is used.Wind farms do not produce any carbon dioxide. Wind farms arenoisy. OR Oil will run out, solar will not. Oil causes air pollution

• the answer communicates ideas clearly and coherently uses a rangeof scientific terminology accurately.

• spelling, punctuation and grammar are used with few errors.


Question Number


2(a)(ii) electron(s) (1)

(1)

Question Number


2(b)(i) evidence of halving activity eg line on graph at 80 (Bq) or two lines at, say, 100 and 50. (1)

8 (days) gains both marks (2)

accept halving in answer space e.g. 160 -> 80 or 80 -> 40or 160 ÷ 2 = 80

NOT 160 ÷ 40 or 131 ÷ {2 or 4} or 40 ÷ 2 (unless clearly an activity)

(2)

Question Number


2(a)(i) proton(s) (1)

NOT photon (1)

Question Number


2(b)(ii) idea of two half-lives (1)

but, 16 (days) gains both marks (2)

halving of 800 twice, e.g. 400 AND 200 seen

Allow ECF from graph eg allow half-life from graph x 2 for both marks (2)


Question Number


QWCC *2( ) A discussion including some of the following points Advantages

- (currently) large resources of fuel/ fuel (reserves) will lasta long time

- (Produces) large amount of (electrical) energy/electricity- Does not produce (much/any) carbon dioxide- Does not produce (much/any) sulphur dioxide- Does not add to global warming/climate change- Good safety record (under normal operating conditions)- Only small amount of fuel needed to produce large amount

of energy/electricity- Reliable supply/provides continuous supply of electricity

(for a long time)- Reduces dependence on foreign supplies of energy

- Conserves fossil fuel supplies- (Spent) fuel can be processed (to produce fuel for other

reactors) - Provides employment/jobs

Disadvantages - Produces nuclear/radioactive {waste/materials}- nuclear/radioactive waste/materials can cause

mutations in DNA/cells/people/animals

- Non- renewable (energy source)- Difficulties in transporting nuclear/radioactive

waste/material - ifficulty in (safely) storing/disposing nuclear

waste/material - Nuclear accidents (can) pollute large areas- Nuclear accidents pollute for a long time- Accept named example of accidents eg Fukishima,

Chernobyl, 3-mile island - Mining and processing fuel both produce large

amounts of carbon dioxide - Expensive to build and/or decommission (nuclear

power stations) - Reference to target for terrorist attacks- Produces material which can be used to develop

nuclear weapons/by terrorists - Negative public perception OWTTE

ignore references such as unsightly, large area needed, noisy as true for most large buildings. Ignore cost of generation or restating stem ie generates electricity or supplies electricity to homes etc.

(6)


(Total for Question 5 =12 marks)

evLevelL No rewardable content 1 1 - 2 • A limited discussion giving one fact

e.g. they give people jobs (in that area)OR they can have accidents like in Japan (after the tsunami).

the answer communicates ideas using simple language and useslimited scientific terminology.

spelling, punctuation and grammar are used with limited accuracy2 3 - 4 A simple discussion that states one advantage and one

disadvantage OR states more than one advantage OR states morethan one disadvantage.e.g. they are a reliable energy source and do not produce any

carbon dioxide.OR they do not cause any global warming as they do not producesulphur dioxide.OR they produce radioactive waste and many people don’t wantthem built.

the answer communicates ideas showing some evidence of clarityand organisation and uses scientific terminology appropriately

spelling, punctuation and grammar are used with some accuracy3 5 - 6 A detailed discussion of either advantages or disadvantages AND

at least a mention of the other one.e.g. They produce large amounts of electricity and don’t produce

carbon dioxide but they produce radioactive materials (in the fuelrods).OR They are a reliable source of energy but they can damage

large areas if there is an accident and the fuel is non-renewable. the answer communicates ideas clearly and coherently uses a

range of scientific terminology accurately spelling, punctuation and grammar are used with few errors


Question Number


3(a)(i) An explanation linking

• 60 % of{total/electrical/input/output}energy (is used/transferred)(1)

• into/is kinetic/useful energy(1)

If no other marks scored accept: 60% (of the energy produced by the motor) is useful/40% is wasted for 1 mark

Accept reverse argument ie

40 % of {total/electrical/input/output} energy (is/transferred)

into/lost as/thermal (heat)/waste energy

(2)

Question Number


3(a)(ii) B energy (1)

Question Number


3(a)(iii) substitution 20 x 15 (1)

evaluation 300 (J) (1)

If no other mark scored award 1 mark for correct transposition ie E= P x t

Ignore any unit given by candidate

Power of 10 error maximum of 1 mark

eg 300 000 (J) gains 1 mark

Give full marks for correct answer, no working

(2)

Question Number


3(a)(iv) substitution 18 ÷ 24 (x 100) (1)

evaluation 0.75 or 75% (1) Ignore any unit given by candidate

Power of 10 error maximum of 1 mark


Question Number


3(b) B conservation of energy (1)



Level Edexcel

Subject Physics





27 minutes

/22

/100

Time Allowed:

Score:

Percentage:



Question Number


1(a) A (1)

Question Number


1(b)(i) both points correctly plotted (1) allow +/- half square (1)

Question Number


1(b)(ii) smooth curve (1) ( does not need to go through all points i.e. can miss out top section)

allow slight discontinuities/double lines/ thick lines

NOT dot to dot /two straight lines (1)

Question Number


1(b)(iii) temperature from 34 °C to 39 °C inclusive (1) (1)

Question Number


1(b)(iv) 21(°C) (1) 22( °C) /23(°C ) (1)

Question Number


1(c)(i) it/black is a good absorber of heat /energy/radiation/IR (1) i.e. it absorbs/takes in moreinfrared/IR

allow it/black absorbs/takes in heat

ignore attracts/emitter/conductor NOT (so it ) cools down quickly (1)


Question Number


1(c)(ii) substitution (1) 9000 ÷ 20

evaluation (1)

450 (W)


e.g. 90 ÷ 2 gains 1 mark45 gains 1 mark


Question Number


1(c)(iii) substitution (1)

9000 ÷ 18 000 ( x 100% )

evaluation (1)

50 (%)


e.g. 90 000 ÷ 1800 gains 1 mark5 gains 1 mark

0.5 or ½ or half gains both marks


(2)


Question Number


2(b)(i)

(ii)

6%

comparing reflected amount for water with any one of the others (1)

100 - 94

saying one {named material (on the graph) is/all materials (on the graph) are} solid

(1)

(1)

Question Number


2(c)(i) An explanation to include the following

• more thermal (heat) energyis absorbed (1)

• because water (liquid)absorbs more than ice (solid)(1)

more radiation is absorbed

because water (liquid) reflects less than ice (solid)

because less ice surface to reflect

because more water surface to absorb (2)

Question Number


2(c)(ii) its temperature rises gets hotter

water level increases/gets higher

Ignore ‘{water/it} {increases/rises}’

Reject toxicity (1)

Question Number


2(a) A (1)


Question Number


QWC *2(d )

A description including some of the following

• solar / heat / light• photosynthesis• chemical / fossil fuel• burning• thermal• in steam• kinetic• in turbine• electrical• in generator (6)


1 1-2 • a limited description which identifies an energy in an appropriate placee.g. thermal energy in the boilerOR e.g. the (same) energy flows from the boiler to the turbine

• the answer communicates ideas using simple language and uses limitedscientific terminology

• spelling, punctuation and grammar are used with limited accuracy2 3-4 • a simple description which includes details of a relevant energy transfer

e.g. (steam causing) the turbine to rotate turns the coil in the generatortransferring kinetic energy into electrical energy

• the answer communicates ideas showing some evidence of clarity andorganisation and uses scientific terminology appropriately

• spelling, punctuation and grammar are used with some accuracy

3 5 - 6 • a detailed description to includes details of a sequence of transfers e.g.chemical energy stored in the coal is transferred in the boiler to thermal energy producing steam. The steam turns the turbine which turns the coil.

• the answer communicates ideas clearly and coherently uses a range ofscientific terminology accurately



energy transfers, gpe, ke & efficiency · 2018. 5. 25. · 3(c)(ii) after falling 50 m / when...

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