Induced Currents and Magnetic Forces Practice Test

Based on the description, a loop rotates in a uniform field in a simple generator so $\Phi=BA\cos(\omega t)$ and $\mathcal{E}=-d\Phi/dt$; reversing flux change reverses current direction (Lenz’s Law), converting mechanical to electrical energy. According to Faraday's Law, what happens to the induced EMF when the magnetic field changes?

According to the scenario, a metal rod of length $\ell$ slides right at speed $v$ on rails in a uniform $\vec B$ into the page, producing motional EMF $\mathcal{E}=B\ell v$ and a current that creates a magnetic force opposing motion (Lenz’s Law), like in rail generators. What is the direction of the induced current in the scenario described?