If the ac peak current through a 100 ohm resistor is 1.7 A, the average power dissipated by the resistance is
A)85 W.
B)170 W.
C)289 W.
D)220 W.
E)145 W.

Question

Quizplus · Accepted Answer

The average power dissipated in a resistor with an AC current is given by P_avg = (I_rms)^2 * R. The RMS current, I_rms, is I_peak / √2. So, I_rms = 1.7 A / √2 = 1.2 A. Therefore, P_avg = (1.2 A)^2 * 100 ohms = 144 W, which is closest to 145 W.

If the Ac Peak Current Through a 100 Ohm Resistor