College Physics 10th Edition by Raymond Serway,Chris Vuille

Exercise 52

A transformer is to be used to provide power for a computer disk drive that needs 6.0 V (rms) instead of the 120 V (rms) from the wall outlet. The number of turns in the primary is 400, and it delivers 500 mA (the secondary current) at an output voltage of 6.0 V (rms). (a) Should the transformer have more turns in the secondary compared with the primary, or fewer turns (b) Find the current in the primary. (c) Find the number of turns in the secondary.