Physics-
General
Easy
Question
A metal disc rotates freely, between the poles of a magnet in the direction indicated. Brushes P and Q make contact with the edge of the disc and the metal axle What current, if any, flows through R?
- a current from P to Q
- a current from Q to P
- no current, because the emf in the disc is opposed by the back emf
- no current, because the emf induced in one side of the disc is opposed by the emf induced in the other side.
The correct answer is: a current from P to Q
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