Explanation:
Eddy currents are produced in a conductor when it is exposed to a changing magnetic field. These currents flow in closed loops and generate heat, which can cause energy losses. The amount of eddy current loss depends on various factors such as the material properties of the conductor, the frequency of the applied voltage, and the shape of the conductor.

Effect of frequency on eddy current loss:
When a conductor is exposed to an alternating voltage, the frequency of the voltage determines the rate at which the magnetic field changes. Therefore, the frequency of the applied voltage has a significant impact on the amount of eddy current loss in the conductor. The following points explain the effect of frequency on eddy current loss:

- At low frequencies, the magnetic field changes slowly, and eddy currents have enough time to build up and flow through the conductor. As a result, eddy current loss is high at low frequencies.
- At high frequencies, the magnetic field changes rapidly, and eddy currents do not have enough time to build up and flow through the conductor. Therefore, eddy current loss is low at high frequencies.
- At a certain frequency, called the skin depth frequency, the eddy currents are mostly confined to the surface layer of the conductor. This is because the skin depth, which is the depth at which the eddy current density has decreased to 1/e (about 37%) of its surface value, becomes smaller than the thickness of the conductor. At this frequency, the eddy current loss is minimum. The skin depth frequency depends on the material properties of the conductor and the frequency of the applied voltage.

Conclusion:
In conclusion, the eddy current loss in a conductor remains unchanged with the increase in frequency of the applied voltage, provided the skin depth frequency is not reached. Beyond the skin depth frequency, the eddy current loss decreases with an increase in frequency. Thus, the correct option is C.

Eddy current losses proportional to B^2 F^2
(P = K B^2 F^2)where B is flux density and F is frequency... flux density = V/F
so with constant voltage P remains unchange...
[P=k (V/F)^2 F^2 ; P= K V^2)