What causes iron losses in a transformer?

Iron losses in a transformer are primarily attributed to two phenomena: eddy currents and hysteresis. When an alternating current flows through the transformer's windings, it creates a changing magnetic field that induces currents within the magnetic core. These induced circulating currents, known as eddy currents, generate heat within the core material, which contributes to energy loss.

Hysteresis loss arises from the magnetic properties of the core material itself. Whenever the magnetic field within the core is reversed (as it is in an AC circuit), some energy is lost due to the inherent resistance of the magnetic material to changes in magnetization. This energy loss is a result of the frictional forces that impede the shifting of magnetic domains in the material, requiring energy that is subsequently dissipated as heat.

Flux leakage, while a consideration in transformer design and efficiency, does not directly contribute to iron losses in the same manner as eddy currents and hysteresis. Thus, the correct choice highlighting the specific causes of iron losses in a transformer is indeed tied to eddy currents and hysteresis, making it the most accurate answer.