One kilowatt hour is the amount of energy delivered during _______________?
Correct answer: D. one hour
- A. one second
- B. one day
- C. one minute
- D. one hour
Explanation
One kilowatt-hour is the energy supplied by a power of 1 kilowatt operating for 1 hour, so the time interval is one hour. Option a, one second, confuses the unit with a much shorter time interval and would give only 1 kilojoule for 1 kilowatt.
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Power is the rate at which work is done or energy is transferred, with average power calculated over a time interval and instantaneous power found from P = Fv when force and velocity are aligned. Work includes units, mechanical efficiency, and the distinction between power and total work or energy.
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