Which unit of measure corresponds to energy in electrical energy consumption?

• A. Watts
• B. Watt-hours
• C. Volts
• D. Amperes (amps)

Answer: (B)

Energy in electrical energy consumption is the amount of work electricity does over time. Power tells us how fast that work happens, measured in watts. To get energy, multiply the power by the time the device runs. One watt-hour is the amount of energy used when a one-watt device runs for one hour, which is 3600 joules. That’s why energy use is commonly billed in kilowatt-hours. For example, a 60-watt bulb used for 5 hours uses 300 watt-hours, or 0.3 kilowatt-hours. The other units describe different things: volts are electrical pressure, and amperes are current. So watt-hours best represents energy in electrical energy consumption.