Question

The magnetic field along the axis of a circular coil is found to be

B = \(\frac{\mu_0Ia^2}{2(r^2+a^2)^{3/2}}\)

1. What is the magnetic field along the axis if r>>a 

2.

• Compare the above magnetic field with the electric field along the axis of an electric dipole
• What is the equation of magnetic dipole moment?

Answer 1

1. B = \(\frac{\mu_0/a^2}{2r^3}\)

2.

• Electric field due to electric dipole,

E = \(\frac{1}{4\pi ε_0}\frac{P}{r^3}\) magnetic field due to magnetic dipole

B = \(\frac{\mu_0}{4\pi}\frac{m}{x^3}\)

• Magnetic moment m = IA