College Physics 10th Edition by Raymond Serway,Chris Vuille

Exercise 40

A step-down transformer is used for recharging the batteries of portable devices. The turns ratio N 2 / N 1 for a particular transformer used in a CD player is 1:13. When used with 120-V (rms) household service, the transformer draws an rms current of 250 mA. Find the (a) rms output voltage of the transformer and (b) power delivered to the CD player.