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- Jan 27th 2007, 01:11 PM #1
## proof2

Hey MathForum,

Im not sure if this is for this section.

The field strength of a magnet*(H)*at a point on the axis, distance from its centre, is given by

where*2l*= length of magnet and*M*= moment. Show that, if*l*is very small compared with , then

How would you solve this question?

Thanks

- Jan 27th 2007, 01:31 PM #2

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- Jan 28th 2007, 02:07 AM #3

- Jan 28th 2007, 03:29 AM #4

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- Jan 28th 2007, 05:56 AM #5

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Hello, dadon!

The field strength of a magnet at a point on the axis,

distance from its centre, is given by: .

where = length of magnet and = moment.

Show that, if is very small compared with , then: .

Combine the fractions: .

The equation becomes: .

If is very small compared to , .then is even smaller.

If we consider to be negligible (virtually zero),

. . the formula becomes: .

- Jan 28th 2007, 08:14 AM #6

- Jan 28th 2007, 08:53 AM #7

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- Jan 30th 2007, 12:15 PM #8

- Jan 31st 2007, 11:58 AM #9

- Feb 3rd 2007, 09:08 AM #10

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- Feb 3rd 2007, 01:26 PM #11