What constitutes one kilowatt-hour (kWh)?

• A. 1,000 watts working for 1 hour
• B. 100 watts working for 10 hours
• C. 10,000 watts working for 0.1 hours
• D. 500 watts working for 2 hours

Answer: (A)

One kilowatt-hour (kWh) is defined as the amount of energy consumed when a power of 1,000 watts is used for one hour. This measurement is a standard unit for billing electricity in homes and businesses, reflecting the total energy consumed over a period of time. When you consider this definition, 1,000 watts running for one hour perfectly describes the energy consumption of 1 kWh.

In the other options, while they may also represent the equivalent of 1 kWh when the calculations are done, they express the concept in different combinations of power and time. For example, 100 watts running for 10 hours indeed results in 1 kWh (100 watts x 10 hours = 1,000 watt-hours), as does the scenario of 10,000 watts working for 0.1 hours (10,000 watts x 0.1 hours = 1,000 watt-hours). Similarly, 500 watts running for 2 hours achieves the same result (500 watts x 2 hours = 1,000 watt-hours). However, the straightforward definition that 1 kWh represents 1,000 watts of power used for one full hour directly aligns with the original, universally accepted definition of a kil