Revision Quesrions Markscheme

Question 1

Explain how rotation is caused in the motor.

Answer 1

• A split - ring commutator ensures the current is flowing in the right direction and changes every half turn (180°)
• flow of current creates a magnetic field
• opposite sides of the coil experience forces in opposite directions

Question 2

Explain Flemings left-hand rule.

Answer 2

Thumb - force
Index/first finger - magnetic field
Middle/second finger - current

Question 3

A teacher places 3 metal foil containers on top of the dome of the Van de Graaff generator. When it’s turned on, the foil containers fly off the dome one by one. Explain why this happens and use charge in your answer.

Answer 3

Charge is transferred
Charge is distributed across the dome or containers
Containers have same charges so they repel OR that electrons repel so charges on a container repel those charges (electrons)