You and a friend are studying late at night. There are three 150 W light bulbs a
ID: 2275028 • Letter: Y
Question
You and a friend are studying late at night. There are three 150 W light bulbs and a radio with an internal resistance of 74.0 ? plugged into the living room electrical outlets. You decide to have a break and have a snack, turning on the pop-corn machine that draws 7.00 A. How much electrical power are you using? Data: Assume the electric company provide you with 110 V potential difference.
All the electrical outlets are part of the same 110-V circuit which has a 10-A circuit breaker. How much current in amperes (A) is required to feed all the devices described above? This tells you if you should or should not turn on the pop-corn machine.
You are so tired after studying that you leave all of these household devices turned on for 10.0 hours. Calculate the cost (in dollars) of the electric bill, if the commercial rate is $.09/kWh? (Do not enter units)
Explanation / Answer
No genius needed just a little arithmetic on your part and the following information.
current (amps) x resistance (ohms) = voltage, (volts)
power (watts)= current (amps) x voltage (volts)
Energy (in electrical units) (watt hours) = power (watts) x the time (hours)
Cost ($) = energy (watt hours) x cost per kilowatt hour (1,000 watt hours)
This is why your parents tell you to turn off the lights.
Also why compact flourescent bulbs cost so much less to use than incandescent (the old round ones). The old type use a lot of watts to produce only a small amount of usable light but give off a lot of heat.
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.