how to calculate joules used to heat
â¦ Some energy is wasted heating the connecting wires because they have some resistance. â¦ The result is a voltage drop along the wire: V = I R and â¦ Joule heating in the wire: Pjoule = I 2 R Both of these effects depend on the current, I, and the resistance, R, but not on the voltage. The connecting wire gets warm from joule heating The bulb filament