Two concentric rings are kept in the same plane. Number of turns in each ring is 25. Their radii are 50 cm and 200 cm and they carry electric currents of 0.1 A and 0.2 A respectively, in mutually opposite directions. The magnitude of the magnetic field produced at their centre is T.

Question

Accepted Answer

(4) 5/4μ₀. Given: N=25 turns in each ring; r₁=50 cm=0.5 m with I₁=0.1 A, r₂=200 cm=2 m with I₂=0.2 A, the currents opposite. Idea: each ring contributes B=(μ₀NI)/(2r) at the common centre; opposite currents put the two contributions in opposite directions, so they subtract. B₁=(μ₀×25×0.1)/(2×0.5)=2.5μ₀ B₂=(μ₀×25×0.2)/(2×2)=1.25μ₀ Net B=B₁-B₂=1.25μ₀=5/4μ₀, in the sense of the inner ring.

Two concentric rings are kept in the same plane. Number of turns in each ring is 25. Their radii are 50 cm and 200 cm and they carry electric currents of 0.1 A and 0.2 A respectively, in mutually opposite directions. The magnitude of the magnetic field produced at their centre is ______ T.

Step-by-step solution

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