Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Doubt in magnetism

  1. Jun 21, 2007 #1
    in higher secondary books i came across magnet's length that is bar magnet's length is given as " 2l" that is 2 multiplied by l. my question is " why the lenght is not referred as 'l' the usual way of referring length.
    please clarify in layman terms.
    thanks in advance
    logesh aravindan
  2. jcsd
  3. Jun 21, 2007 #2
    i am a poor one in english but iff i understund : they make that in order to have a simple formula ;because(may be) they will divid by 2 so in the place to have this ugly (l/2) they just have this beautiful (l). and i recall that in the baccalaureat exam of this year ,they gave us (2l) in order to pertutbate you .
  4. Jun 25, 2007 #3
    i dont understand please clarify lucidly
  5. Jun 25, 2007 #4
    I would have to see the book, but I'm assuming the l is refering to the lenght of a single pole, so the total length of the magnet is 2l. That is l of the north and l of the south combined.

    CraigD, AMInstP
  6. Jun 25, 2007 #5


    User Avatar
    Gold Member

    arkhammedos is right. Often the length is given as '2l' so the 2 will cancel out and leave a cleaner expression.

    It is like choosing radius and not diameter so we can write [tex]A=\pi r^2[/tex] and not [tex] A=\frac{\pi D^2}{4}[/tex]
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook