Question: One particular plug-in power supply for a radio looks similar to the one shown in Figure 33.23 and is marked with the following information: Input

One particular plug-in power supply for a radio looks similar to the one shown in Figure 33.23 and is marked with the following information: Input 120 V AC 8 W Output 9 V DC 300 mA. Assume that these values are accurate to two digits.
(a) Find the energy efficiency of the device when the radio is operating.
(b) At what rate does the device produce wasted energy when the radio is operating?
(c) Suppose that the input power to the transformer is 8.0 W when the radio is switched off and that energy costs $0.135/kWh from the electric company. Find the cost of having six such transformers around the house, plugged in for thirty-one days.

Step by Step Solution

3.48 Rating (155 Votes )

There are 3 Steps involved in it

1 Expert Approved Answer
Step: 1 Unlock

a b c Input power 8 W Useful output power IAV03 A... View full answer

blur-text-image
Question Has Been Solved by an Expert!

Get step-by-step solutions from verified subject matter experts

Step: 2 Unlock
Step: 3 Unlock

Document Format (1 attachment)

Word file Icon

P-M-A-C (50).docx

120 KBs Word File

Students Have Also Explored These Related Electricity and Magnetism Questions!