Final answer:
Energy consumption is sometimes listed in kilowatt-hours instead of joules because kilowatt-hours combine power and time. The relationship between the two units is that 1 kilowatt-hour is equal to 3.6 x 10^6 joules.
Step-by-step explanation:
The energy consumption in kilowatt-hours (kWh) is sometimes used instead of joules to measure energy consumption because the kilowatt-hour is a unit that combines power and time.
Power is the rate at which energy is used or transferred, while energy is the capacity to do work. Kilowatt-hours represent the total amount of energy consumed over a period of time and are commonly used in electricity bills.
The relationship between kilowatt-hours and joules can be understood by knowing that 1 kilowatt-hour is equal to 3.6 x 10^6 joules.
This conversion factor allows us to convert between the two units.
For example, if a device has a power rating of 100 watts and it is used for 5 hours, the energy consumed can be calculated by multiplying the power (in kilowatts) by the time: 0.1 kilowatts x 5 hours = 0.5 kilowatt-hours.
This measurement in kilowatt-hours provides a practical and convenient way to measure and estimate energy usage.