# Question: The transformer on a utility pole steps the voltage down

The transformer on a utility pole steps the voltage down from 10 000 V to 220 V for use in a college science building. During the day, the transformer delivers electric energy at the rate of 10.0 kW.

(a) Assuming the transformer to be ideal, during that time, what are the primary and secondary currents in the transformer?

(b) If the transformer is only 90% efficient (but still delivers electric power at 10.0 kW), how does its input current compare to the ideal case?

(c) At what rate is heat lost in the nonideal transformer?

(d) If you wanted to keep the transformer cool and to do this needed to dissipate half of the joule heating of part (c) using water cooling lines (the other half is taken care of by air cooling), what should be the rate of flow (in liters per minute) of water in the lines? Assume the input cool water is at and the maximum allowable output water temperature is 98oF.

(a) Assuming the transformer to be ideal, during that time, what are the primary and secondary currents in the transformer?

(b) If the transformer is only 90% efficient (but still delivers electric power at 10.0 kW), how does its input current compare to the ideal case?

(c) At what rate is heat lost in the nonideal transformer?

(d) If you wanted to keep the transformer cool and to do this needed to dissipate half of the joule heating of part (c) using water cooling lines (the other half is taken care of by air cooling), what should be the rate of flow (in liters per minute) of water in the lines? Assume the input cool water is at and the maximum allowable output water temperature is 98oF.

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