Explanation: In an AC circuit, the power factor is defined as the cosine of the phase angle (θ) between the voltage and the current. It represents the ratio of true power (or real power) to apparent power. Given a phase angle of 30 degrees: Power Factor (PF) = cos(θ) PF = cos(30°) The value of cos(30°) is approximately 0.866. Therefore, the power factor in this R-L circuit is 0.866. * **A) 1.73:** This is √3, not a cosine value for 30 degrees. * **C) 0.5:** This would be the power factor for a 60-degree phase angle (cos(60°)). * **D) 0.577:** This is approximately tan(30°) or 1/√3.