Please check my answers:

why does an iron core increase the magnetic iduction of a coil of wire?
-I am thinking it has something to do with the voltage being increased.

Will a cyclist coast farther if the lamp is connected to the generator on his bicycle is turned off?
-I say no because the generator is not producing engergy or voltage

1 answer

An iron core increases the magnetic B field coil by aligning some electron orbits within the iron.

A light generator will slow down a bike if the light is on, and the bike will not coast as far.