The energy delivered by an induced current ultimately comes from
- A. the magnetic field, which is used up
- B. the mechanical work done against the opposing force predicted by Lenz's law
- C. nothing, since it is created by induction
- D. the resistance of the circuit
Explanation
Because the induced effect opposes the motion, whoever moves the magnet or turns the generator must do work, and that mechanical work is converted into electrical energy. This is why a bicycle dynamo makes pedalling harder once the lamp is switched on. A magnetic field is not consumed in the process.
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