Save My Exams! – The Home of Revision For more awesome GCSE and A level resources, visit us at www.savemyexams.co.uk Page 1 Permanent and induced magnetism Mark Scheme 1 Level GCSE (9-1) Subject Physics Exam Board AQA Topic 4.7 Magnetism and electromagnetism Sub-Topic Permanent and induced magnetism Difficulty Level Bronze Level Booklet Mark Scheme 1 Time Allowed: 27 minutes Score: /27 Percentage: /100
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Page 1
Permanent and induced magnetism
Mark Scheme 1
Level GCSE (9-1)
Subject Physics
Exam Board AQA
Topic 4.7 Magnetism and electromagnetism
Sub-Topic Permanent and induced magnetism
Difficulty Level Bronze Level
Booklet Mark Scheme 1
Time Allowed: 27 minutes
Score: /27
Percentage: /100
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Page 2
M1. (a) induced 1
(b) bar 2 1
(the same end) of bar 1 attracts both ends of bar 2
or
only two magnets can repel so cannot be bar 1 or bar 3 1
(c) so the results for each magnet can be compared
or
so there is only one independent variable
fair test is insufficient
allow different thickness of paper would affect number of sheets each magnet could hold
accept it is a control variable 1
(d) because the magnet with the biggest area was not the strongest
accept any correct reason that confirms the hypothesis is wrong eg smallest magnet holds more sheets than the largest
1
[5]
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M2. (a) (i) field pattern shows:
some straight lines in the gap 1
direction N to S
1
(ii) north poles repel 1
(so) box will not close 1
(b) (i) as paper increases (rapid) decrease in force needed 1
force levels off (after 50 sheets) 1
(ii) the newtonmeter will show the weight of the top magnet 1
(iii) (top) magnet and newtonmeter separate before magnets separate
accept reverse argument 1
(because) force between magnets is greater than force between magnet and hook of newtonmeter
1
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(iv) any three from:
• means of reading value of force at instant the magnets are pulled apart
• increase the pulling force gently or
use a mechanical device to apply the pulling force • clamp the bottom magnet • use smaller sheets of paper • fewer sheets of papers between readings (smaller intervals) • ensure magnets remain vertical • ensure ends of magnet completely overlap • repeat the procedure several times for each number of sheets and
take a mean • make sure all sheets of paper are the same thickness
3
(v) 3 (mm)
30 × 0.1 ecf gains 2 marks
2.1 N corresponds to 30 sheets gains 1 mark 3
[15]
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M3. (a) (i) increase 1
(ii) A and B and B and C
both required for the mark
either order 1
(iii) any two from:
• size of nail or
nail material
allow (same) nail
• current
allow (same) cell
allow p.d.
same amount of electricity is insufficient
• (size of) paper clip
• length of wire
accept type / thickness of wire 2
(b) 4 1
B picks up the same number as C, so this electromagnet would pick up the same number as A or
direction of current does not affect the strength of the electromagnet
allow it has got the same number of turns as A 1
(c) 2
allow 1 or 3 1
[7]
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Permanent and induced magnetism
Mark Scheme 1
Level GCSE (9-1)
Subject Physics
Exam Board AQA
Topic 4.7 Magnetism and electromagnetism
Sub-Topic Permanent and induced magnetism
Difficulty Level Silver Level
Booklet Mark scheme 1
Time Allowed: 28 minutes
Score: /28
Percentage: /100
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M1. (a) plastic or rubber
accept any named plastic do not accept wood
1
it is a (good) insulator or it is a poor conductor
ignore mention of heat if in conjunction with electricity 1
(b) The answer to this question requires ideas in good English in a sensible order with correct use of scientific terms. Quality of written communication should be considered in crediting points in the mark scheme.
Maximum of 2 marks if ideas not well expressed.
pulls iron bolt down or attracts the iron bolt or moves bolt out of plunger
answers in terms of charges attracting or repelling gain no credit
1
plunger pushed / moved to the right (by spring) or plunger released 1
push switch opens / goes to off / goes to right
accept circuit is broken
for maximum credit the points must follow a logical sequence
3 correct points but incorrect sequence scores 2 marks only
ignore reset action 1
[5]
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M2. Quality of written communication: One mark for correct sequencing.
bolt out plunger up switch off / circuit broken 1
any five from
• high current flows
• electromagnet is stronger
• the iron bolt is pulled out
• the plastic plunger moves up
• the switch is lifted / open / off
accept circuit is broken
• no current flowing
• to re-set the plunger must be pushed down 5
[6]
M3. electromagnet becomes stronger (not becomes magnetic) iron moves left – implied
OK plunger goes up push switch goes to off or circuit broken unless plunger moves down
for 1 mark each [4]
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M4. (i) relay
accept solenoid
do not accept magnetic switch 1
(ii) a current flows through the coil (of the electromagnet) or a current flows through the electromagnet or a (magnetic) field is produced
accept ‘electricity’ for ‘current’
accept the electromagnet is activated or magnetised or turned on
do not accept answer in terms of magnetic charge 1
the (iron) arm is attracted to the electromagnet
accept the arm pivots or moves towards the electromagnet 1
the contacts are pushed together
do not accept contacts attract 1
[4]
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M5. (a) current flows
coil / core magnetised / electromagnet activated / energised / turned on attracts iron bar causing bolt to be pulled out
each for 1 mark 4
(b) more turns bigger current / e.m.f softer iron core
any two for 1 mark each 2
(c) to relock door / return iron bar / to lock door
for 1 mark 1
(d) iron bar would still be attracted / coil still magnetised so still works
for 1 mark each
yes + wrong answer
0 marks
yes + current still flows
1 mark
yes + still magnetised / iron bar still attracted
2 marks 2
[9]
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The Motor effect
Mark Scheme 1
Level GCSE (9-1)
Subject Physics
Exam Board AQA
Topic 4.7 Magnetism and electromagnetism
Sub-Topic Motor effect
Difficulty Level Silver Level
Booklet Mark scheme 1
Time Allowed: 48 minutes
Score: /48
Percentage: /100
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M1.(a) move a (magnetic / plotting) compass around the wire 1
the changing direction of the compass needle shows a magnetic field has been produced
OR
sprinkle iron filings onto the card (1)
tapping the card will move the filings to show the magnetic field (pattern) (1) 1
(b) Level 2 (3–4 marks): A detailed and coherent explanation is provided. The response makes logical links between clearly identified, relevant points that explain how the ignition circuit works.
Level 1 (1–2 marks): Simple statements are made. The response may fail to make logical links between the points raised.
0 marks:
No relevant content.
Indicative content
• closing the (ignition) switch causes a current to pass through the electromagnet
• the iron core (of the electromagnet) becomes magnetised • the electromagnet / iron core attracts the (short side of the ) iron arm • the iron arm pushes the (starter motor) contacts (inside the electromagnetic
switch) together • the starter motor circuit is complete • a current flows through the starter motor (which then turns)
4
[6]
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M2. (a) (i) it moves or experiences a force horizontally to the right
for 1 mark 1
(ii) A – moves in opposite direction or force reversed e.c.f. B – faster movement or larger force (not move further)
for 1 mark each 2
(b) turns clockwise oscillates/reverses comes to rest facing field/at 90o to field/vertically
for 1 mark each 3
(c) number of turns or linear number density of turns current core
for 1 mark each 3
[9]
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M3. (a) increase the current (1)
credit increase the p.d./voltage credit reduce the resistance credit have thicker wiring credit add extra / more cells
1
increase the magnetic field (strength) (1)
credit ‘have stronger magnet(s) do not credit ‘bigger magnets’ either order
1
(b) either reverse polarity
or connect the battery the other way round 1
either reverse direction of the magnetic field
or put the magnet the other way round / reverse the magnet
do not give any credit to a response in which both are done at the same time
either order 1
(c) either
conductor parallel to the magnetic field
or lines of magnetic force and path of electricity do not cross 1
[5]
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M4. (a) electric drill, electric fan, electric food mixer and electric screwdriver
all four ticked and no others (2)
either all four of these ticked and only one other (1)
or any three of these ticked and none/one/two of the others (1)
2
(b) (i) reverse (the direction of the) current (1)
or reverse the connections (to the battery)
reverse (the direction of the) magnetic field (1)
or reverse the (magnetic) poles /ends
do not credit ‘swap the magnets (around)’ 2
(ii) any two from:
• increase the strength of the magnet(s)/(magnetic) field
do not credit ‘use a bigger magnet’
• increase the current
allow ‘increase the voltage/p.d.’ allow add cells/batteries allow increase the (electrical) energy allow increase the power supply allow ‘decrease the resistance’ allow ‘increase charge’ allow ‘ increase the electricity’
do not credit ‘use a bigger battery’
• reduce the gap (between coil/armature and poles/magnets)
allow increase the (number of) coils
• increase the turns (on the coil/armature)
do not credit ‘use a bigger coil’ 2
[6]
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M5.(a) move a (magnetic / plotting) compass around the wire 1
the changing direction of the compass needle shows a magnetic field has been produced
OR
sprinkle iron filings onto the card (1)
tapping the card will move the filings to show the magnetic field (pattern) (1) 1
(b) Level 2 (3–4 marks):
A detailed and coherent explanation is provided. The response makes logical links between clearly identified, relevant points that explain how the ignition circuit works.
Level 1 (1–2 marks):
Simple statements are made. The response may fail to make logical links between the points raised.
0 marks:
No relevant content
Indicative content • closing the (ignition) switch causes a current to pass through the
electromagnet • the iron core (of the electromagnet) becomes magnetised • the electromagnet / iron core attracts the (short side of the ) iron arm • the iron arm pushes the contacts (inside the electromagnetic switch)
together • the starter motor circuit is complete • a current flows through the starter motor (which then turns)
4
[6]
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M6. (a) centre of the X midway between the poles
intention correct as judged by eyeexample
1
(b) move the poles further apart
accept turn for move
accept ends / magnets for poles
accept use weaker magnets
do not accept use smaller magnets 1
(c) (i) add more cells (to the battery)
do not accept ‘use a bigger battery’
accept increase the potential difference / voltage
accept increase the current
orreduce the resistance (of the variable resistor)
do not accept any changes to the magnets, to the wire or to their relative positions
1
(ii) reverse (the polarity of) the battery
accept turn the battery / cells round
accept swap the connections to the battery
do not accept any changes to the magnets, to the wire or to their relative positions
1
[4]
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M7. (a) (i) an electrical conductor 1
(ii) increase current
accept increase p.d. / voltage oruse stronger magnets
accept move magnets closer
do not accept use larger magnets 1
(iii) reverse the poles / ends (of the magnet)
either order 1
reverse the connections (to the power supply) 1
(b) (i) environmental 1
(ii) ethical
allow political (instability)
allow economic (migration) 1
[6]
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M8. (a) (i) an electric motor 1
(ii) force 1
(b) any two from:
• more powerful magnet
do not allow ‘bigger magnet’
• reduce the gap (between magnet and coil)
• increase the area of the coil
• more powerful cell
do not allow ‘bigger cellߣ
accept battery for cell
accept add a cell
accept increase current / potential difference
• more turns (on the coil)
allow ‘more coils on the coilߣ
do not allow ‘bigger coilߣ
2
(c) reverse the (polarity) of the cell
allow ‘turn the cell the other way round’
accept battery for cell 1
reverse the (polarity) of the magnet
allow ‘turn the magnet the other way up’ 1
[6]
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magnetic field 1
(creating) a force (acting) on XY / wire / upwards
reference to Fleming's left hand rule is insufficient 1
(ii) motor (effect) 1
(iii) vibrate / move up and down 1
5 times a second
only scores if first mark point scores
allow for 1 mark only an answer ‘changes direction 5 times a second’
1
(b) 0.005
allow 1 mark for calculating moment of the weight as 0.04 (Ncm)andallow 1 mark for correctly stating principle of momentsorallow 2 marks for correct substitution
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• fewer batteries have to be made
• less raw materials are used in making batteries
• customers have to replace their batteries less often
longer lifetime is insufficient
• customers have to buy fewer (replacement) batteries
it costs less is insufficient 1
[8]
M7.Marks awarded for this answer will be determined by the Quality of Written Communication (QWC) as well as the standard of the scientific response. Examiners should also apply a
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‘best-fit’ approach to the marking.
0 marks No relevant / correct content.
Level 1 (1–2 marks) Either there is an attempt at a description of the construction of a transformer
or
a correct statement of the effect of one type of transformer on the input p.d.
Level 2 (3–4 marks) There is a description of the construction of a transformer and a correct statement of the effect of one type of transformer on the input p.d.
Level 3 (5–6 marks) There is a clear description of the construction of a transformer and there is a correct description of how transformers affect the input p.d.
details of construction:
extra information
a (laminated) core
core is made from a magnetic material / iron
2 coils
the coils are made from an electrical conductor / copper
the coils are covered in plastic / insulation
the coils are (usually) on opposite sides
step-up transformer has more turns on secondary coil than (its) primary (or vice versa)
step-down transformer has fewer turns on secondary coil than (its) primary (or vice versa)
effect on input p.d. :
step-up transformer, the output p.d. is greater (than the input p.d.)
accept voltage for p.d.
step-down transformer, the output p.d. is lower (than the input p.d.) 6