Question

The rechargeable batteries for a laptop computer need a much smaller voltage than what a wall socket provides. Therefore, a transformer is plugged into the wall socket and produces the necessary voltage for charging the batteries. The batteries are rated at 9.0 V, and a current of 212 mA is used to charge them. The wall socket provides a voltage of 120V.

(a) Determine the turns ratio of the transformer.
(b) What is the current coming from the wall socket?
(c) Find the average power delivered by the wall socket and the average power sent to the batteries.