Homework Help: physics

Posted by Kristie on Thursday, April 19, 2012 at 12:07pm.

In periods of peak demand, power companies lower their voltage. This saves them power (and saves you money!). To see the effect, consider a 1200- W coffeemaker that draws 10 A when connected to 120 V. Suppose the voltage is lowered by 13 % to 104 V.(Caution: The 1200- W label is valid only when 120 V is applied. When the voltage is lowered, it is the resistance of the toaster, not its power, that remains constant.)
1)By how much does the current decrease?
2)By how much does the power decrease?

physics - Henry, Friday, April 20, 2012 at 10:26pm
R = 120V / 10A = 12 Ohms.

1. I = V/R = 104 / 12 = 8.67 Amps.
Change = 10 - 8.67 = 1.33 Amps.

2. P = VI = 104 * 8.67 = 902 Watts.
Change = 1200 - 902 = 298 Watts.

Answer this Question

Related Questions

physics - In periods of peak demand, power companies lower their voltage. This ...
math - In A Year, Seema Earns RS 1,50,000. Find The Ratio Of Money That Seema ...
physics - I'm supposed to design a PV system that could provide an average ...
physics - During a “brownout,” which occurs when the power companies ...
college albegra - Brandon has 3 inventions, one saves 30 percent on fuel; a ...
science - what happens to the power of an electric circuit if the resistance is ...
PHYSICS - The peak value of the ac current in a circuit is 6.0 A, and peak value...
math - every week Brady gets $2.50 more for his allowance than Max does. They ...
Math - Please help! Suppose one girl saves $10 every week. Another girl already ...
Circuts - A wye-connected load consists of three impedances of 12+j3 ohms each. ...

For Further Reading

First Name:
School Subject:
Answer: