The two main losses of the transformer are called _______ and copper losses.

• A. Iron
• B. Core
• C. Flux
• D. Resistance

Answer: (A)

The main idea is that transformer losses fall into two big categories: losses in the magnetic core and losses in the windings. The losses in the core are called iron losses, which come from the iron’s magnetic properties as it continuously magnetizes and demagnetizes with the alternating current. These include hysteresis losses and eddy current losses within the core. The losses in the windings are copper losses, which arise from the resistance of the winding conductors and cause heat proportional to I squared R, increasing with the load.

So the blank is filled with iron, giving iron losses and copper losses. Flux-related losses aren’t a standard category on their own, and resistance alone doesn’t capture the full idea of the core versus winding losses, while core is close but the established pairing used here is iron losses with copper losses.