PHYSICS · Subjective · CBSE · Physics · Moving Charges and Magnetism · Moving Charges and Magnetism
Problem
Two identical closely wound circular coils, each of N turns and radius R, are mounted coaxially one above the other with negligible separation.
The coils are connected to the same d.c. source in two different ways:
(a) in series, so that the same current I₀ flows through both coils,
(b) in parallel, so that the total current drawn from the source remains I₀ and, because the coils are identical, the current divides equally between them.
(i) Derive the ratio of the magnetic dipole moments of the composite coil system in cases (a) and (b).
(ii) For N = 100, R = 0.10 m and I₀ = 5.0 A, calculate the magnetic dipole moment in each case.
(iii) Explain physically why connecting the coils in series produces a larger dipole moment than connecting them in parallel.