1. The problem statement, all variables and given/known data [Broken] Part f. Calculated current = 0.5 A. Voltage = 30 V. Resistance = 40 Ω 2. Relevant equations P=IV P=I^2*R P=V^2/R 3. The attempt at a solution I've been curious about this for a while. Sometimes when I am asked to find the power dissipated through a resistor, and I use P=IV, it doesn't yield the same answer as if I used P=I^2*R, which is generally the correct answer. This is such an example. P=IV yields 15 W, while P=I^2*R yields 10 W, which is the correct answer. Can anyone explain this? And under which circumstances should I use P=I^2*R, and under which circumstances should I use P=IV? Thanks in advance!