The power supply for your answering machine is a small black cube that plugs directly into an electric outlet. The main component in this supply is a transformer and moderate current from the 120 volt power line flows through the primary coil of this transformer. If the transformer's primary coil has 20 times as many turns of wire in it as the secondary coil has, then the secondary coil provides
A) a larger voltage and a larger current than the primary.
B) a smaller voltage and a larger current than the primary.
C) a smaller voltage and a smaller current than the primary.
D) a larger voltage and a smaller current than the primary.

Question

Quizplus · Accepted Answer

The transformer reduces the voltage by a factor equal to the ratio of turns between the primary and secondary coils. With fewer turns in the secondary coil, the voltage is reduced. According to the principle of energy conservation, if the voltage decreases, the current increases, assuming power remains constant.

The Power Supply for Your Answering Machine Is a Small