Question

an electric current is produced using a bar magnet and a solenoid. which changes will cause a decrease in the electric current produced? check all that apply. using more wire loops in the solenoid using fewer wire loops in the solenoid using a stronger magnet moving the solenoid instead of the magnet moving the magnet more slowly

Explanation:

Step1: Recall Faraday's law

Induced emf $\epsilon = -N\frac{\Delta\Phi}{\Delta t}$, where $N$ is number of loops, $\Delta\Phi$ is change in magnetic - flux and $\Delta t$ is time interval. Current $I=\frac{\epsilon}{R}$ (by Ohm's law, $R$ is resistance).

Step2: Analyze effect of number of loops

More loops ($N$) increase induced emf and current. Fewer loops ($N$) decrease induced emf and current. So using fewer wire loops in the solenoid will decrease current.

Step3: Analyze effect of magnet strength

A stronger magnet increases magnetic - flux $\Phi$, increasing induced emf and current.

Step4: Analyze motion

Moving the solenoid or magnet creates relative motion for flux - change. Moving the magnet more slowly decreases $\frac{\Delta\Phi}{\Delta t}$, decreasing induced emf and current.

Answer:

using fewer wire loops in the solenoid, moving the magnet more slowly