The correct answer is: C. increase
Iron losses are the losses in a transformer that are due to the eddy currents and hysteresis losses in the transformer’s core. Eddy currents are induced currents that flow in the core of the transformer due to the changing magnetic field. Hysteresis losses are due to the movement of the magnetic domains in the core of the transformer as the magnetic field changes.
The frequency of the supply voltage determines the rate at which the magnetic field in the core of the transformer changes. As the frequency increases, the rate at which the magnetic field changes also increases. This causes the eddy currents and hysteresis losses to increase.
Therefore, if the supply frequency to the transformer is increased, the iron losses will increase.
Here is a more detailed explanation of each option:
- Option A: not change. This is not correct because the iron losses will increase as the frequency increases.
- Option B: decrease. This is not correct because the iron losses will increase as the frequency increases.
- Option C: increase. This is the correct answer because the iron losses will increase as the frequency increases.
- Option D: any of the above. This is not correct because the iron losses will increase as the frequency increases.