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Q & A: magnetic generators

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Most recent answer: 06/04/2008
Q:
Is the electrical power made by a spinning magnet inside a coil of wire,affected by the speed of how fast it (the magnet)turns? I've found a way to make the magnet spin very fast with very little energy. Thank you for your help. David A.
- David A. (age 11)
Center School, Longmeadow, MA
A:
The good news is that the power does increase with speed. The bad news is that if you put your magnet inside a coil in a circuit that lets the current flow, there will be a torque from the coil slowing down the magnet. You will never get more power out than you put in. That's the first law of thermodynamics.

Mike W.

(published on 06/04/2008)

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