| ΔV2 |
 |
| P |
| 1202 |
|
| 100 |
Let's use the power equation to calculate the resistance of a 100 W light bulb. The bulb's power is 100 W when the potential difference is 120 V, so we can find the resistance from:
| R | = |
|
= |
|
= | 144 Ω |
We can check this by measuring the resistance with a ohm-meter.