ELECTRIC CHARGE
3 marks · NormalA student says that rubbing a plastic rod with a cloth creates new charge. Explain why this statement is incorrect.
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No new charge is created. Friction causes electrons to be transferred from one material to the other, separating existing charges; total charge is conserved.
Must show: Charge is neither created nor destroyed, Friction transfers electrons, Charges are separated, not created
Also accept: The act of rubbing separates existing charges by moving electrons, but does not create new charge
Common mistakes: Stating charges are created
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Marking points
B1 · 1 mark · States that new charge is not created.
B1 · 1 mark · Mentions transfer of electrons moves existing charges.
B1 · 1 mark · Notes conservation of charge.
Worked solution
Rubbing a plastic rod with a cloth does not create new charge. Instead, electrons are transferred from one object to the other, separating existing charges. The overall amount of charge stays the same as charge is conserved.