If the current in an electric bulb decreases by 0.5%, the power in the bulb decreases by approximately:
Correct answer: A. 1%
- A. 1%
- B. 0.5%
- C. 2%
- D. 0.25%
Explanation
Power dissipated is given by P = I²R. For small percentage changes, the percentage change in power is approximately twice the percentage change in current. Therefore, a 0.5% decrease in current results in an approximate 2 × 0.5% = 1% decrease in power.
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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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