One way to state Lenz's Law is that "The direction of the induced current is such that the induced magnetic field opposes the change in the flux." Another way to state the law is that "The direction of the induced current opposes its cause." You might find this second form useful for this activity. (a) A bar magnet falls towards a circular loop of wire as shown. The falling magnet induces a current in the wire. What is the direction of the induced current? The induced field exerts a force on the falling magnet. What is the direction of the force exerted by the wire on the magnet? Explain. (b) The magnet has fallen past the loop of wire and is now accelerating away from it. Now, what is the direction of the induced current? What is the direction of the force exerted by the wire on the magnet? Explain. (c) The magnet is falling away from the loop as in the previous Part B, but the poles of the magnet are reversed. What is the direction of the induced current? What is the direction of the force exerted by the wire on the magnet? (d) If your answer in Parts A, B, and C were opposite to the correct answers, what physical principles would this violate?