Permeability in a magnetic circuit corresponds to ................in an electric circuit

Question

Examoogle · Accepted Answer

Conductivity

Explanation: Permeability (\mu) in a magnetic circuit is the measure of the ease with which a magnetic flux can pass through a material, which is analogous to conductivity (\sigma) in an electric circuit. Both represent the ability of a medium to support the flow of a field (magnetic flux or electric current) in response to a driving force (MMF or EMF).

Working Principle: In an electric circuit, current (I) is driven by EMF (V) through conductance (G), where $I = G 	imes V$. Similarly, in a magnetic circuit, flux (\Phi) is driven by MMF (F) through permeance (P), where $\Phi = P 	imes F$. Since permeance $P = \frac{\mu A}{l}$ and conductance $G = \frac{\sigma A}{l}$, permeability ($mu$) directly maps to conductivity (\sigma) as the material property dictating the ease of flux or current establishment.

Key Formulas: $\Phi = \frac{F}{R_m} = P \cdot F$ — Magnetic Ohm's Law where P is Permeance; $I = \frac{V}{R} = G \cdot V$ — Electric Ohm's Law where G is Conductance; $\mu = \mu_0 \mu_r$ — Absolute permeability definition; $\sigma = \frac{1}{ho}$ — Conductivity as reciprocal of resistivity

Key Points: Permeability (\mu) represents how easily a magnetic field is established in a medium.; Conductivity (\sigma) represents how easily an electric current flows through a conductor.; Reluctance (R_m) is the magnetic equivalent of electrical resistance (R).; Permeance (P) is the reciprocal of Reluctance (R_m), analogous to Conductance (G).

Advantages: Simplifies complex magnetic circuit calculations using electrical network theorems.; Allows usage of KVL and KCL analogs (Hopkinson's Law) for magnetic systems.

Disadvantages: Magnetic circuits are non-linear due to saturation (B-H curve), unlike standard ohmic resistors.; Magnetic leakage flux makes the simple circuit model an approximation.

Applications: Transformer core design.; Electric machine (motors/generators) flux path analysis.; Magnetic shielding materials.

Additional Info: Option D (Resistivity) is the reciprocal of conductivity; it corresponds to Reluctivity ($v = 1/\mu$).. Option A (Resistance) corresponds to Reluctance (R_m).

Answer: C is correct — Permeability is the magnetic equivalent of conductivity as both quantify the ease of maintaining a flux or current field.

Exam Tip: Always remember: Permeance is to Conductance as Reluctance is to Resistance; permeability and conductivity are the material-specific constants.

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