(a) Define the term magnetic dipole moment for (i) a current-carrying loop and (ii) a bar magnet.
(b) Show qualitatively that for a single circular loop the magnetic dipole moment is directly proportional to the product of the current in the loop and the area it encloses, whereas for a bar magnet it is proportional to the product of its pole strength and the distance between the poles.
(c) A circular loop of radius r is said to be equivalent to a bar magnet of length 2ℓ. Identify the physical quantity that must be equal for this equivalence to hold and briefly explain why.
b. (b) Show qualitatively how the magnetic dipole moment for a single circular loop depends on the loop current I and the area A it encloses, and similarly, how for a bar magnet it depends on its pole strength and the distance between its poles.
c. (c) A circular loop of radius r is said to be equivalent to a bar magnet of length 2ℓ. Identify the physical quantity that must be equal for this equivalence to hold and briefly explain why.