Reluctance in a magnetic circuit is most analogous to which electrical quantity?

• A. Capacitance
• B. Inductance
• C. Relative permeability
• D. Resistance

Answer: (D)

Reluctance measures how strongly a magnetic circuit resists the passage of magnetic flux, like how resistance resists electric current. In a magnetic circuit, the magnetomotive force drives flux through reluctance according to F = Rm × Φ. This mirrors Ohm’s law V = I × R, where voltage drives current through resistance. So reluctance plays the same role as resistance: higher reluctance means less flux for the same driving force, just as higher resistance yields less current for the same voltage. Reluctance depends on length, cross-sectional area, and material permeability (Rm = l/(μA)); increasing length or decreasing area or lowering permeability raises reluctance, just as increasing length or resistivity or decreasing area raises resistance. Inductance concerns energy storage during changing currents and is about opposition to changes in current over time, not a static opposition to flow. Capacitance stores energy in an electric field and isn’t the direct obstacle to flux in a magnetic circuit. Relative permeability is a material property that scales how easily flux can pass, not a circuit-level opposition quantity.