The equivalence between a coil carrying current and a bar-magnet can be shown as:

According to the Biot - Savart law the intensity of magnetic field due to current in the coil of figure 1 (a)s on its axis is given by :

whereas, for bar-magnet in figure 1 (b), we have shown earlier in Chapter 20 that :-

On comparison between magnetic fields due to current carrying loops and bar magnets, it is obvious that a current carrying loop has associated with it the dipole moment .

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Index

Origin of Magnetism

27.1 Diamagnetism, Paramagnetism and Ferromagnetism
27.2 Theory of Diamagnetism and paramagnetism
27.3 Theory of Ferromagnetism and curie temperature of Ferromagnets

Chapter 28