Charging materials by friction
3 marks · NormalA plastic ruler is tested in a circuit as shown.
Describe the change in brightness of the lamp if a copper rod replaces the plastic ruler. Explain your answer.
Suggest another material you could test that would behave the same as copper.
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(a) The lamp becomes brighter (lights), because copper is a conductor and allows current to flow.
(b) Graphite
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Marking points
M1 (a) · 1 mark · States the lamp becomes brighter/lights.
M1 (a) · 1 mark · Explains this is because copper allows current to flow (conductor).
B1 (b) · 1 mark · Correctly gives another conductor (e.g. graphite or another metal).
Worked solution
a) The lamp becomes brighter or switches on. This is because copper is a conductor and allows current to flow, unlike plastic.
b) Graphite (lead in pencils) would also conduct and behave the same way.