If a bulb has a 20W power. If it is working at 60% efficiency, then its output power is:
Correct answer: A. 12W
- A. 12W
- B. 15W
- C. 20W
- D. 18W
Explanation
efficiency = output/input × 100output = (efficiency × input)/100output = 12W
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About Current Electricity
Steady current relates charge flow to potential difference, resistance and resistivity, including how temperature changes a conductor's resistance. Sources with internal resistance have terminal voltage below their emf when delivering current, and maximum power output occurs under a specific load condition rather than at zero resistance.
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