A. Core loss
B. Copper loss
C. Both core & copper loss
D. None of the above
Answer: B. Copper loss
Explanation:
Copper loss is due to the ohmic resistance of the transformer windings.
The copper loss for the primary winding is (I1)2 × R1 and for secondary winding is (I2)2 × R2.
Where I1 and I2 are current in primary and secondary winding respectively.
R1 and R2 are the resistances of primary and secondary winding respectively.
It is clear that Cu loss is proportional to the square of the current, and current depends on the load.
Hence copper loss in the transformer varies with the load.