Question

1. a student is designing a simple generator using a coil of wire and a rotating magnet. which of these changes would most effectively increase the electrical output of the generator?

increasing the number of turns in the coil of wire
using a plastic coil instead of a metal one
placing the magnet farther away from the coil
rotating the magnet at a slower speed
clear all

Explanation:

To determine which change increases a generator's electrical output, we analyze each option:

• Increasing the number of turns in the coil: Generators work via electromagnetic induction. The induced electromotive force (emf) is given by Faraday’s law, \( \mathcal{E} = -N\frac{\Delta\Phi}{\Delta t} \), where \( N \) is the number of turns. Increasing \( N \) increases the induced emf, thus increasing electrical output.
• Using a plastic coil: Plastic is an insulator and does not conduct electricity, so no current would be induced, reducing output.
• Placing the magnet farther away: This weakens the magnetic field through the coil, reducing the magnetic flux change (\( \Delta\Phi \)) and thus the induced emf.
• Rotating the magnet slower: A slower rotation rate reduces \( \frac{\Delta\Phi}{\Delta t} \) (since flux changes more slowly), decreasing the induced emf.

Only increasing the number of coil turns effectively boosts output.

Answer:

A. Increasing the number of turns in the coil of wire