why magnet's length is '2l'?

Question

hi friends,
please clarify the reason for referring magnet's length as '2l', instead of usual 'l' in magnetism? please help friends

Answer 1

Where did you see that? I've never used anything but "l" (and infrequently even that). A Horseshoe magnet might involve a 2l somehow. The other case is in an equation what has some sort of square term. The 2 might come from integrating something?

Usually when they do that it's to make some computation easier. Physicists do it with violin strings, tubes for making sound, and a bunch of other stuff.

I wonder if when they do that they're assuming that the fields are symmetrical? BAD assumption!

Answer 2

Maybe in practice magnetic fields are hard to make symmetrical, but in theory a bar magnet is symmetrical, and some of the mathematically described properties of either pole would be a function of the pole's distance from the center. The equations can be simpler if they refer to this distance as L rather than L/2, and thus one would call the magnet length 2L.