If the peak value of current and voltage are doubled, then what is the percentage change in average power?
Correct answer: A. 300%
- A. 300%
- B. 200%
- C. 100%
- D. None
Explanation
Average power P (avg) = (I (peak) × V (peak) )/2. If both I (peak) and V (peak) are doubled, the new average power P' (avg) = (2I (peak) × 2V (peak) )/2 = 4 × P (avg) . An increase by a factor of 4 is a 300% increase from the original value.
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Alternating current varies periodically, so phase relationships become essential when current passes through a resistor, capacitor or inductor. The chapter distinguishes resistance from capacitive and inductive reactance, explains phase lead and lag, and connects changing electric and magnetic fields with the production and properties of electromagnetic waves.
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