Which property of silicon steel contributes to its suitability for transformer cores?

• A. Low density
• B. High permeability
• C. High thermal conductivity
• D. High stiffness

Answer: (B)

High magnetic permeability is what makes silicon steel well suited for transformer cores. Permeability measures how easily a material allows magnetic flux to pass through it. A core with high permeability offers a very low reluctance path for the magnetic field created by the transformer's windings, so less magnetizing current is needed to establish the same flux. That means energy is transferred more efficiently from the primary to the secondary, with lower losses related to magnetization.

Silicon steel achieves this favorable behavior while also resisting losses at AC frequencies; the silicon content increases electrical resistivity, which helps limit eddy currents that would otherwise waste energy and degrade performance. The combination of high permeability and reduced eddy current losses is why silicon steel is used for transformer cores. The other listed properties—density, thermal conductivity, and stiffness—don’t directly influence how effectively the core channels magnetic flux.