Magnetic moment of compass needle?

[shoestring]

What would be a typical value of the magnetic moment of a compass needle (in SI units)?

Thanks :-)

 

[cragar]

Do you know the B field of the needle? If you do try to model the needle as a little current loop, Use the biot savart law to find what current your loop needs to produce that B field. Your loop will have a diameter equal to the length of the needle.
Then just multiply the current times area
M=I(area)
Maybe you could find the B field of the needle by dropping it through a coiled copper wire and relating the change in flux to the voltage .

 

[Naty1]

Lots here, but not a typical value stated, and in the links at the bottom of the article:

http://en.wikipedia.org/wiki/Magnetic_moment

Looks like you can calculate a value...

 

[shoestring]

Thanks both, but I'm a little confused about the units. The strength of a magnet is given in Tesla, but that isn't the same as magnetic moment, is it? Obviously I need to read up on magnetism.

The reason I'm wondering is that I'd like to compare the magentic dipole moment of a compass needle with the induced electric dipole moment it might get in a strong electric field, to see if an electric field could possible cause any deviation of the needle.

 

[sardar]

The magnetic moment of a compass needle refers to its ability to align with the Earth's magnetic field. It is a measure of the strength and direction of the magnetic field produced by the needle. In SI units, the magnetic moment is typically measured in units of ampere-meter squared (A m^2). The exact value of the magnetic moment of a compass needle can vary depending on its size, material, and the strength of the Earth's magnetic field at its location. However, a typical value for a small compass needle can range from 10^-6 to 10^-5 A m^2. It is important to note that the magnetic moment of a compass needle can also change over time due to factors such as temperature and external magnetic fields.