The magnitude of the dipole moment associated with an atom ofiron in an iron bar is 2.1X10-23 J/T. Assume that allthe atoms in the bar, which is 4.7 cm long with a cross sectionalarea of 1.1 cm2, have their dipole moments aligned.
a) What is the dipole moment of the bar?
b) What torque must beexerted to hold this magnet perpendicular to an external field ofmagnitude 1.5 T? (The density of iron is 7.9 g/cm3)