Eddy Currents

As discussed in NCERT Class 12, Chapter 6 (Electromagnetic Induction), eddy currents are circulating currents induced in bulk conductors when the magnetic flux through them changes, and by Lenz's law they dissipate energy as heat while opposing the flux change. In a solid core, large closed loops of low resistance allow substantial eddy currents and heavy losses. Laminating the core into thin sheets separated by insulating varnish breaks these large loops into many small high-resistance paths, sharply reducing the induced currents and the associated heating. The option about increasing flux is wrong; laminations do not enhance flux and slightly reduce cross-sectional metal. The option about eliminating winding insulation confuses core laminations with winding insulation, which are separate. The option about reducing mass is irrelevant, since the purpose is electrical, not mechanical response. A plausibility check: because power loss scales with the square of the induced current, even a modest rise in resistance from lamination greatly lowers wasteful heating, improving transformer efficiency.