Lenz’s Law states that the current induced in a metal object will oppose the change when it experiences a change in flux, such as a moving magnetic field. As seen the formula below contains a negative value, since the induced emf is negative.
The emf that is induced is due to eddy currents which are created in the magnetic material experiencing the change in flux.
We will go into the theory of this in greater depth in a following lesson.
Question 1. [Not an exam style question]
Knowing an emf must be induced in order for the demonstration above to work, predict whether a plastic tube will make the object fall faster, slower or no effect on a falling magnet compared to the magnet falling through a copper tube.