Question

A toaster is plugged into an 120-volt outlet. If it has a resistance of 460 ohms, how much power does it use?
A. 1,800 watts
B. 3.8 watts
C. 31 watts
D. 55,000 watts
E. 340 watts

Answer 1

Power is generally given by the formula
\[P = IV\] but by utilizing Ohm's law..
\[R = \frac{ V }{ I } \rightarrow I=\frac{ V }{ R }\]
Plugging this into the original power equation we have
\[P = (\frac{ V }{ R }) V = \frac{V^{2}}{R}\]
Now just use the values you know for Voltage and Resistance!

Answer 2

Thanks!

Answer 3

You're welcome! Power can also be rearranged to just include current and resistance, so just be aware of that!

Answer 4

Okay (:

Answer 5

Do you get my other question ?