Question

A British bicycle light company advertises flashing bicycle lights that require no batteries and produce no resistance to riding. A magnet attached to a spoke on the bicycle tire moves past a generator coil on the bicycle frame, inducing an emf that causes a light to flash. The magnet and coil never touch. Does this lighting system really produce no resistance to riding? Justify your answer.

Answer 1

Lenz's law is responsible for the resistance to advance due to the change in magnetic flux

Step-by-step explanation:

This system produces electricity by Faraday's law,

E = - d / dt B.A

Where the electromotive force is generated by the change of the field strength maintained due to the circular movement of the wheel.

As this field changes when Lenz's law increases or decreases, it creates a field that opposes this change, this field is applied to the bicycle and is in the opposite direction to movement, so it is an effect that creates resistance to the advance of the bike.

In summary Lenz's law is responsible for the resistance to advance due to the change in magnetic flux