What is a kilowatt-hour used to measure?

A kilowatt-hour is a unit of energy that specifically measures the amount of energy consumed when a device utilizes 1,000 watts for one hour. This concept is foundational in understanding energy consumption for electrical devices. When you consider that 1 kilowatt equals 1,000 watts, it becomes clear that if a device operates continuously at this power level for one hour, it will consume a total of 1 kilowatt-hour of energy.

This measurement is crucial for utility companies and consumers alike as it directly relates to how electricity is billed. The kilowatt-hour represents a practical way to quantify energy use, as it connects the power rating of a device (in watts) with the time it operates.

The other choices, while similar in nature, do not accurately illustrate the standard definition of a kilowatt-hour. They involve different timeframes or misunderstood applications of power versus energy, which do not align with the precise measurement that “kilowatt-hour” is designed to represent. Understanding that it specifically refers to energy consumption over an hour makes option A the correct choice.