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Average power dissipated
A resistor of R= 50 ohms is connected to an AC power supply of 200 V, what is the average power dissipated by the resistor? I thought this was straightforward and I just had to use P=V^2/R, but that isn't the right answer apparently.
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Notice that the power supply is AC, alternating current. The equation you provided, P = V^2/R gives the instantaneous power, or the power dissipated at any given moment in time. However, the voltage V is oscillating, or changing with time! To find the average power in an AC circuit you need to use the RMS voltage.
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Notice that the power supply is AC, alternating current. The equation you provided, P = V^2/R gives the instantaneous power, or the power dissipated at any given moment in time. However, the voltage V is oscillating, or changing with time! To find the average power in an AC circuit you need to use the RMS voltage.