Calculate the rate at which energy is transferred by a 220 V mains supply, which provides a current of 0.1 A to an LED?
Correct answer: D. 22 W
- A. 2.2 W
- B. 2.2 kW
- C. 22 kW
- D. 22 W
Explanation
Power = Voltage x Current; 220 x 0.1 = 22W
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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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