In a RL circuit with a 60-degree phase difference between voltage and current, what is the power factor?

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Multiple Choice

In a RL circuit with a 60-degree phase difference between voltage and current, what is the power factor?

Power factor is the cosine of the phase angle between voltage and current. In an RL circuit, the current lags the voltage, and here that phase difference is 60 degrees. So the power factor is cos(60°) = 0.5. This means only half of the apparent power is doing real work. The other values would correspond to smaller phase differences (cos 45° ≈ 0.707, cos 30° ≈ 0.866) or no phase difference (cos 0° = 1), which don’t match a 60-degree lag.

Power factor is the cosine of the phase angle between voltage and current. In an RL circuit, the current lags the voltage, and here that phase difference is 60 degrees. So the power factor is cos(60°) = 0.5. This means only half of the apparent power is doing real work. The other values would correspond to smaller phase differences (cos 45° ≈ 0.707, cos 30° ≈ 0.866) or no phase difference (cos 0° = 1), which don’t match a 60-degree lag.

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