10 kilowatt-hours is enough energy to run a 1,000-watt waffle iron for how long?

10 kilowatt-hours is enough energy to run a 1,000-watt waffle iron for how long?

• A. 5 hours
• B. 1 hour
• C. 10 hours
• D. 20 hours

Answer: (C)

Understanding how energy, power, and time relate helps here: energy equals power times time. A 10 kilowatt-hour amount of energy can run a device that uses 1 kilowatt of power for a certain number of hours. Since 1,000 watts is 1 kilowatt, the time you can run the waffle iron is 10 kWh divided by 1 kW, which equals 10 hours. In other words, using the waffle iron at full power for ten hours would consume about 10 kWh. (For reference, using it for one hour would use about 1 kWh.)

Understanding how energy, power, and time relate helps here: energy equals power times time. A 10 kilowatt-hour amount of energy can run a device that uses 1 kilowatt of power for a certain number of hours. Since 1,000 watts is 1 kilowatt, the time you can run the waffle iron is 10 kWh divided by 1 kW, which equals 10 hours. In other words, using the waffle iron at full power for ten hours would consume about 10 kWh. (For reference, using it for one hour would use about 1 kWh.)