An electric hotplate has a power rating of 1440 W and a current draw of 12 A. What is the resistance of the hotplate?
The quantity to be found is resistance, and the known quantities are power and current. Use the formula shown in Figure 2–23.
R=\frac{P}{I^2}
R=\frac{1440 ~W}{12 ~A \times 12 ~A}
R=\frac{1440 \mathrm{~W}}{144 \mathrm{~A}}
\mathrm{R}=10 ~\Omega