What unit is used to express electrical energy?

• A. Watt (W)
• B. Joule (J)
• C. Ohm (Ω)
• D. Volt (V)

Answer: (B)

The unit used to express electrical energy is the Joule (J). This is because energy is defined as the capacity to do work, and in electrical terms, the Joule quantifies the amount of energy transferred when an electric current flows through a circuit. Specifically, one Joule is equivalent to the energy transferred when one coulomb of electric charge is moved through an electrical potential difference of one volt.

While the Watt (W) is a unit of power that measures the rate at which energy is consumed or produced (equivalent to one Joule per second), it does not directly quantify energy itself. Ohms (Ω) represent electrical resistance, and Volts (V) indicate electrical potential or voltage, neither of which directly measure energy. Thus, Joule is the appropriate unit for expressing electrical energy in this context.