# Lenz' Law and Electric Generators

• Lenz' Law describes the direction in which induced voltage causes current to run around a loop: the voltage pushes the current in the direction which will oppose the change in magnetic flux through the loop.
• In other words, Lenz' Law states that induced currents try to maintain the original magnetic flux through a loop of wire (even though they don't quite make it).
• Most electrical generators turn mechanical energy into a voltage via magnetic induction. Lenz' Law shows why the voltage produced by such generators alternates sign.
• The maximum voltage produced by a generator of area A rotating in a magnetic field B at a rate of w radians per second is
```               V(max)  =  N * A * B * w
```
where N is the number of turns in the rotating loop.
• Note that the angular velocity w (radians/second) is related to the period P (seconds) and frequency f (1/second) of rotation as follows:
```                                     2*pi
w  =  2*pi*f  = ------
P
```
• Also note that the maximum voltage V(max) is 1.41 times larger than the RMS voltage; people usually use the RMS voltage to describe ordinary wiring, such as 120-volt circuits in the home.

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