Voltage Dropped and Power Dissipated Across a Series Resistor

Any resistor in a circuit that has a voltage drop across it dissipates elecrical power. This electrical power is converted into heat energy, hence all resistors have a power rating. This is the maximum power that can be dissipated from the resistor without it burning out. The rate of conversion is the power of dissipation.

Power dissipation is a measure of how much power (P = I x E) in a circuit is converted into heat.