The general formula for power dissipation is: Power = Current x Voltage However, if you only know the voltage and the resistance, you can calculate the current using Ohm's Law, which is usually given as: Voltage = Current x Resistance However, you can rearrange this to give: Current = Voltage/Resistance You can then substitute this into the expression for power dissipation to yield an equation that gives an expression for power in terms of only voltage and resistance: Power = [tex] Voltage^{2}[/tex] / Resistance
