A coil has resistance R and inductance L. At ω = ∞, the phase angle between voltage and current is _____________

Concept & ReasoningThe phase angle of an R-L coil is φ = tan⁻¹(ωL/R). At very low frequency the resistive term can dominate and φ approaches 0°. As frequency increases, inductive reactance grows linearly with ω. In the limit ω → ∞, ωL/R → ∞ and tan⁻¹(∞) = 90°. Thus the coil behaves like an ideal inductor in the high-frequency limit.How to Solve It in the ExamHigh frequency makes an RL coil increasingly inductive.Important Exam PointUse the limiting form of tan⁻¹(ωL/R).Related Revision PathThis question sits in the revision path Basic Electrical Engineering → AC Circuits → Series RL Circuit .