With reference to Lenz's Law explain why it is harder to turn a generator when it is connected to a load (e.g. a light bulb) than when it is connected to a load?
Please help
Thanks
When a generator turns in a magnetic field, it experiences a change in flux
This change in flux induces an EMF
A current will only flow through the coils in the generator if the generator is connected as part of a circuit (i.e., has a load)
When the induced current flows it creates a force which opposes the motion of the generator (Lenz' law), thus making it harder to turn due to the resistive forces.
This is where a great deal of students mess up in my experience.
EMF is
ALWAYS induced whenever there is a change in flux
Current is only created if the coils experiencing a change in flux are connected to an external circuit to allow the electrons to utilise the potential difference.
Current is what provides the resisitive force (according to Lenz' Law), therefore only a resistive force if a current flows.
