Give an example of an electrical device that runs on DC. Explain how the device has to be adapted so that it can be plugged into the AC mains supply.

You decide to “go green" and use an exercise bike to power your home appliances. Assume that your exercise bike is rigged to generate electrical power with 60% efficiency. In other words, only 6/10 of the power you develop can be used to store electrical energy for later use. Consider your 3500-Watt central AC unit. You need to run this unit for 4 hours each day during the summer. If you can develop a sustained power of 300 Watts on your exercise bike, how long would you have to work out just to keep the AC running on a summer day?

A 115-W light bulb operates on an effective ac voltage of 110 V. NOTE: This is a multi-part question. Once an answer is submitted, you will be unable to return to this part.  What is the effective current through the light bulb?

The primary circuit in a transformer carries a current of 4.0 A at 120 V. The secondary circuit of a transformer carries 1.0 A of current. If only 90.0 % of the power is transmitted from the primary circuit to the secondary circuit, what is the voltage of the secondary circuit?