Mark schemes
(a) repel
1. 1
opposite
1
attract
1
correct order only
(b) refuelling an aircraft
reason cannot score if refuelling aircraft is not chosen
1
a spark may cause an explosion / fire / ignite the fuel
accept the static for a spark
accept named fuel
there must be a consequence of having a spark
do not accept answers in terms of people getting a shock or
electrocuted
1
[5]
(a) fleece rubs against shirt
2.
it refers to the fleece
1
or
friction (between fleece and shirt)
(causing) electrons to transfer from one to the other
accept a specific direction of transfer
do not accept charge for electrons
positive electrons negates this mark
movement of protons negates this mark
1
(b) Electrical charges move easily through metals.
1
An electric current is a flow of electrical charge.
1
(c) (i) copper
reason only scores if copper chosen
1
(good electrical) conductor
accept it is a metal
any mention of heat conduction negates this mark
1
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(ii) lower than 1
(iii) accept any sensible suggestion,eg:
• too many variables (to control)
• lightning strikes / storms are random / unpredictable
• do not know which building will be struck
• do not know when a building will be struck
• do not know when lightning will happen
• (very) difficult to create same conditions in a laboratory
• lightning storms are not the same
it is not safe is insufficient
do not accept lightning does not strike the same place twice
1
[8]
(a) transfer of electrons
3.
mention of positive charge moving negates both marks
1
from the carpet to the student
1
(b) three arrows perpendicular to sphere’s surface with all arrows directed inwards and
distributed evenly around sphere
1
(c) there is a potential difference between the student and the tap
do not accept the tap / sink is charged
1
which causes electrons / charges to transfer from the student
or
which causes electrons / charges to transfer to the tap
1
which earths the charge
allow the tap is earthed
1
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(d) carpet / copper has a low resistance
allow carpet is a conductor
or
copper is a conductor
1
lower / no build-up of charge (on the student)
or
(so there is a) smaller / no potential difference between student and tap / earth
1
[8]
(a) electrons
4. 1
(b) a positive
1
(c) the forces are repulsive
allow the forces act in opposite directions
1
the forces are equal in size
allow the forces are the same (size)
1
(d) reproducible
1
[5]
(a) Level 2 (3–4 marks):
5. A detailed and coherent explanation is provided. The student makes logical links between
clearly identified, relevant points.
Level 1 (1–2 marks):
Simple statements are made, but not precisely. The logic is unclear.
0 marks:
No relevant content
Indicative content
• friction (between cloth and rod) causes
• electrons (to) move
• from the acetate rod or to the cloth
• (net) charge on cloth is now negative
• (net) charge on rod is now positive
4
(b) there is a force of attraction between the acetate rod and the cloth
(reason)
1
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unlike charges attract
or
negative charges attract positive charges
1
(c) increase
1
(d) 0.000025 × 60 000
1
1.5 (J)
1
accept 1.5 (J) with no working shown for 2 marks
[9]
(a) 3rd box
6.
The negative charge in the water is repelled by the rod and
the positive charge is attracted.
1
(b) (i) friction between bottles and conveyor belt / (plastic) guides
accept bottles rub against conveyor belt / (plastic) guides
1
charge transfers between bottles and conveyor belt / (plastic) guides
accept specific reference
eg electrons move onto / off the bottles
reference to positive electrons / protons negates this mark
1
(ii) an atom that has lost / gained electron(s)
do not accept a charged particle
1
(iii) charge will not (easily) flow off the conveyor belt
accept the conveyor belt / bottle is an insulator / not a conductor
accept conveyor belt is rubber
1
[5]
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