A circular parallel-plate capacitor is being charged by a constant current. Let B₁ be the magnetic field between the plates at r = R/2 and B₂ the magnetic field at r = 2R. If B₁/B₂ = N, find N.

Question

G1 Physics · Accepted Answer

For r<R, B = μ₀Ir/(2πR²). At r = R/2, B₁ = μ₀I/(4πR). For r>R, B = μ₀I/(2πr). At r = 2R, B₂ = μ₀I/(4πR). Therefore, B₁/B₂ = 1. Hence N = 1.