Question

many bicycles have generators that have a light that can be powered without a battery. instead of a battery, a magnet and a coil of wire are used to make an electric current flow. the setup shown below models how a bicycle generator functions to produce light. currently, no electric current is flowing through the circuit shown. what needs to happen to cause an electric current to flow through the circuit? a. the magnet needs to be in constant motion. b. a smaller wire needs to be used. c. a bigger light bulb needs to be used. d. the magnets north pole needs to point up.

Explanation:

According to Faraday's law of electromagnetic - induction, an electric current is induced in a circuit when there is a changing magnetic flux through the coil. Moving the magnet creates a changing magnetic field around the coil, which induces an electric current. Changing the wire size, bulb size, or the orientation of the magnet's north - south poles (without motion) does not induce a current.

Answer:

A. The magnet needs to be in constant motion.