What is a watt-hour (Wh)?

• A. A measure of electrical power
• B. A measure of electrical energy used for one hour
• C. The maximum output of a generator
• D. A unit of electrical resistance

Answer: (B)

A watt-hour (Wh) is defined as a measure of electrical energy used for one hour. This unit quantifies the amount of energy consumed when a device uses one watt of power for one hour. In practical terms, if an appliance operates at a power level of one watt for an entire hour, it would consume one watt-hour of energy.

This understanding is crucial in various applications, such as billing for electricity usage, where consumption over time is calculated in watt-hours or kilowatt-hours (kWh). Each of the other options represents different aspects of electrical principles: power is measured in watts, a generator's maximum output relates to its capacity in terms of power, and resistance is measured in ohms. However, the specific concept of watt-hour directly relates to energy consumption over time, making it a distinct and important unit in the context of electrical energy usage.