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Magnet science

  1. Jun 6, 2010 #1


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    hey guys,

    i was wondering if there was a formula to measure the strength of a magnet in relation to its size, and what else is needed to be known before such a value can be computed.

    e.g. its shape, lets say a bar magnet

    (you have my apology if i have posted in the wrong forum, but i'm conducting a non-school project with a friend- we are building something in his garage. Not very sure where i should post this. we need to use an magnet to move an object. since we are building a project, we have to consider the size of the magnet used. Is there a way to solve this?)

    thanks in advance
  2. jcsd
  3. Jun 6, 2010 #2


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    70+ views and no answers...?
    come on guys a little help please..

    thanks again
  4. Jun 7, 2010 #3
    how about this make a solenoid by wrapping copper wire around something , you can calculate the field strength of this by using B=(mu)NI/(H) where (mu) is the magnetic permeability constant and N is the number of turns in the coil , I is the current in the wire and H is the height of the coil . then you could take a balance and put a piece of iron on one end and it would stick to the electromagnet and then you could place weight in the other end to see how much force it would require to pull it off the magnet and then you could try to find a bar magnet about this same force , but if the bar magnet was slightly different in strength just vary the numbers of turns in your solenoid to match the field strength of your bar magnet , then you could calculate the field strength of based on the current and the number of turns in your coil and compare it to your bar magnet , or if you could get your hands on an electron gun you could calculate the force of the magnet using the lorentz force and how much your electromagnet deflected the electron beam and relating it to the centripetal force .
    Hope this helps , i don’t know if this is quite what your looking for .
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