I am doing an expirement where i have a magnet inside of a copper coil which is connected to a voltage meter, and i‘m wondering if when the magnet is spun on it‘s axis if it will induce a current in the coil. Does the axis on which itspins afeect this or not? Does the coil have to be bare wire or can it be insulated?
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Will a spinning Neodymium Magnet induce a current in the copper coil which surrounds it? Yes, if the coil is oriented in such a way that it cuts the magnetic field lines. I am doing an experiment where i have a magnet inside of a copper coil which is connected to a voltage meter, and I am wondering if when the magnet is spun on its axis if it will induce a current in the coil. Does the axis on which it spins affect this or not? Yes, the axis is crucial. It is not really practical to set up a spin such that there is no current induced, but the orientation is important to get optimum results. Imagine that the Earth is a perfect magnet with north and south poles and perfectly aligned field lines, rotating as the Earth actually does. A coil of wire going around the equator would likely not have current induced, due to the fact that the coil would not be effectively cutting field lines. Making the earth rotate such that the poles went end over end would be an optimal orientation. Does the coil have to be bare wire or can it be insulated? It does not matter, but it helps to have lacquered wire and many loops of wire (instead of just one loop). The gauge of the wire does not really affect the result, but thinner wire is easier to loop multiple times in a small volume of space. I suppose that if you are generating high enough currents, the resistance in thinner wire and the heat generated may become a problem (generator windings usually breakdown because of overheating). Good luck!
Good question. The law of physics describing induction (the process of inducing a potential because of a changing magnetic field) is Faraday's Law of Induction. It might be useful to read about it. Briefly, Faraday's law states that the magnitude of the current generated is proportional to the rate of change of the magnetic field with time (the first time derivative). The magnetic field needs to be changing with time. If you have a cylindrical or bar magnet, the magnetic field is called cylindrically symmetric. Consider the Earth. Assume (for the sake of argument) that the magnetic north and south agreed with the true north and south poles. The axis of rotation of the Earth is through the true North and South poles; however, the magnetic field doesn't change as you vary your longitude. Traveling east/west doesn't change the magnetic field - it's cylindrically symmetric. The Earth rotating about its axis causes no oscillation in time of the magnetic field (or a very small one). The same is true of your magnet. Suppose, instead of rotating the magnet around the axis given by its N/S ends, you rotate the magnet end over end (so the North and south poles change direction while you rotate it). The magnetic field is massively varying. It's difficult to illustrate this without more geometry, but I hope that's clear. It would be an interesting part of your experiment if you tested the size of the voltage generated by rotating the magnet across various axes. The orientation of the magnet relative to the coils is also important. On the wire: insulation does not block magnetic fields (unless it's REALLY good insulation), so it shouldn't matter if its insulated. If it's not insulated, it's very important the wire not touch itself in the coil, or the coil will be useless. I recommend using insulated wire.
