The magnitude of the dipole moment associated with an atom ofiron in an iron bar is 2.1 10-23J/T. Assume that all the atoms in the bar, which is 5.8 cm long and has a cross-sectional area of1.1 cm2, have their dipolemoments aligned.
(a) What is the dipole moment of the bar?
Am2
(b) What torque must be exerted to hold this magnet perpendicularto an external field of 1.0 T? (Thedensity of iron is 7.9 g/cm3.)
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