Magnet strength?

Question

Can a permanent magnets strength be increased by wrapping a coil around it, and then running a current though this coil? Also if this can be done what direction must the coil run in relation to the +/- ends of the magnet. Lastly, how much of an increase in strength can you get?

Answer 1

When you coil metal wire around any object and run a current thought it, you create a solenoid through the inside, perpendicular to the wire.  Solenoids are used to create electromagnets.

The direction of the magnetic field can be found by taking your right-hand and coiling your fingers in the direction of the current through the wires.  Then, if you point your thumb out it will be pointing in the direction of the magnetic field.  Magnetic field "flows" in the negative direction (current flows from negative to positive)

The magnetic field is increased by increasing the number of turns and the length of wire used.  It is important to make sure that you are looping the wire in the same direction.  

Wrap from one end to the other, then take the wire back to the start and wrap in the same direction.  This is important, because if done incorrectly it will create opposing magnetic fields which will cancel each other out.

Answer 2

magnets don't have +/- ends.

If you got the polarity correct, you would remagnetize the magnet at a higher level, unless it was already as high as it could go.

How much increase depends on how strong it was to start with. There is a limit to how powerful a permanent magnet can be and that depends on the material.

Answer 3

Eu sei, que tal vc se danar

Answer 4

Yes.

You mean + being a North pole and - being a South pole.

Use the right hand rule for conventional current.

A long straight coil of wire can be used to generate a nearly uniform magnetic field similar to that of a bar magnet. Such coils, called solenoids, have an enormous number of practical applications. The field can be greatly strengthened by the addition of an iron core. Such cores are typical in electromagnets.

Holding a bar magnet with N to the left wrap the wire starting at the S end and go clockwise around the bar.  Conventional current will flow from the right end of the wire around the coil out the left end.