Question

Why is the induced current greatest when a generator's loop is in the direction of the magnetic field?

Answer 1

This self-induced emf will, by Lenz's law oppose the change in current in the coil and because of its direction this self-induced emf is generally called a back-emf. Lenz's Law states that: ” the direction of an induced emf is such that it will always opposes the change that is causing it”.

Answer 2

using the formula

I∝dΦ/dt=AdB⃗ n⃗ dt=ddtABcosωt=−ABωsinωtI∝dΦ/dt=AdB→n→dt=ddtABcos⁡ωt=−ABωsinωt