Question

For the electric power transmission system shown in the figure above, what is the ratio ns/np for the step-up transformer? assume 100% efficiency.

Answer 1

I am attaching the missing figure

If we assume 100% efficiency, this means that the input power of the transformer must be equal to the output power

We divide output/input

240,000/12,000 = 20

This means that the transformer has a turns ratio of 1:20

ns/np = 20/1 = 20

The voltage is amplified 20 times by the transformer, but this also means that the current decreases by a factor of 20, so the total power remains the same.