Lenz's Law is said to be a consequence of the principle of conservation of energy. Explain this statement by describing what would happen if Lenz's Law were reversed. Take the example of a wire loop with a changing magnetic flux, and describe what would happen if current were induced opposite to the way it really is.

Let's say you take an ordinary wire coathanger and straighten out the hook shaped part that normally hangs over the coatrack. Now, you can spin the (roughly) triangular part around by twisting the straightened part between your fingers. Estimate the EMF that you can generate by spinning the hanger in the Earth's magnetic field (about 5 x 10^-5 T).

A wire hoop (shown in blue) surrounds a long solenoid. If the current in the solenoid increases, will there be any current induced in the loop? If so, which way will the current flow?

An moderately priced voltmeter can easily measure a voltage of 1 mV. If you run with the probes in your outstretched arms, the Earth's magnetic field will induce a voltage. Estimate how fast you would need to run to register 1 mV. Can you do it? In what direction should you run for maximum effect?