Heat generated by a 40 W bulb in an hour is
Correct answer: D. 144000 J.
- A. 40 J.
- B. 90 J.
- C. 2400 J.
- D. 144000 J.
Explanation
Energy (E) = Power (P) × Time (t)Given:Power (P) = 40 WTime (t) = 1 hourFirst, convert the time from hours to seconds, as 1 Watt is equal to 1 Joule per second (J/s).1 hour = 60 minutes1 minute = 60 secondsSo, 1 hour = 60 × 60 = 3600 seconds.Now, calculate the energy:E = 40 W × 3600 sE = 144000 J
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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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