A circuit that includes a resistor stores how much energy compared to an identical circuit without a resistor?

• A. More energy
• B. Less energy
• C. The same energy
• D. No energy

Answer: (B)

Resistors dissipate energy as heat and do not store energy themselves. If you compare two identical circuits where one includes a resistor and the other does not, the circuit with the resistor ends up storing less energy in any energy-storage elements (like a capacitor or inductor) because part of the energy from the source is lost as heat in the resistor. A helpful example is charging a capacitor through a resistor: some of the energy from the source goes into heating the resistor, and only part of it is stored in the capacitor. So, the circuit with the resistor stores less energy.