If the voltage of a circuit is 12 V, and the resistance is 40 Ω, what is the power generated?

Even though it isn’t possible to solve it only using the equation P = IV, we can combine

it with the equation V = IR, removing the variable we are not given and we are not solving for, in this case, I. We now combine the equations and get P = V^{2}/R.

We plug in our known values and get P = 144/40 = 3.6 W.