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

Homework Help: Testing the field strength of a permanent bar magnet

  1. Aug 3, 2011 #1
    I've just completed a prac, where a beam was placed into a solenoid with a current flowing through it, causing a force to exerted down and I balanced out the force by placing weights on the other end in the effort of calculating the magnetic field strength. Anyway, one of the short answer questions given states:
    "Could this apparatus be used to find the field strength of a small permanent bar magnet? Discuss the process and describe the limitations."

    The relevant equation used to calculate the magnetic field strength was: B = mg/IL. However, this problems is largely theory based.

    I assume that if a permanent bar magnet was placed within a solenoid which had current flowing through it, that the magnetic field lines would interfere with another and cause the direction of the force caused by the magnetic field on the perpendicular section of the magnet to the field lines (according to the Right Hand Slap Rule) to not act directly downwards so that I could counteract it by placing weights on the other end of the magnet, but I'm clearly finding difficulty.

    Thanks for reading, and I would greatly appreciate help. (NOTE: I apologize if this in the wrong section of the forum, this is my first post)
  2. jcsd
  3. Aug 3, 2011 #2


    User Avatar
    Homework Helper

    I think the suggestion was "can you use a similar set-up using a small permanent magnet instead of the solenoid with a fixed current"
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook