A ring of radius R has uniformly distributed charge. It spins about its axis with an angular velocity ω. P is a point on its axis at a distance x from its centre. The velocity of light in vacuum is c. The ratio of the magnetic field to the electric field at P is proportional to-
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Question

A ring of radius R has uniformly distributed charge. It spins about its axis with an angular velocity ω. P is a point on its axis at a distance x from its centre. The velocity of light in vacuum is c. The ratio of the magnetic field to the electric field at P is proportional to-

Select all that apply

G1 Physics · Accepted Answer

For a rotating charged ring, magnetic dipole moment μ∝qωR². Far on the axis, B∝μ/x³ while electric field E∝q/x². Hence B/E∝ωR²/x. Therefore A,B,C are correct.

A ring of radius R has uniformly distributed charge. It spins about its axis with an angular velocity ω. P is a point on its axis at a distance x from its centre. The velocity of light in vacuum is c. The ratio of the magnetic field to the electric field at P is proportional to−