Consider a series RLC circuit driven at a fixed angular frequency that is higher than…
PHYSICS · Multi-part · A Level · Physics · Fields and their consequences · Fields and their consequences
Problem
Consider a series RLC circuit driven at a fixed angular frequency ω that is higher than its resonant angular frequency ω0. Let the circuit parameters be L=80mH and C=5.0μF.
(i) Show algebraically that, for a fixed ω, the phase angle ϕ tends to +90∘ (pure lag) as the resistance R tends to zero, and to 0∘ as R becomes very large.
(ii) Take ω=1.5ω0. Calculate ϕ (in degrees) for two cases: (a) R=1Ω and (b) R=100Ω.
(iii) Comment briefly on how the resistance influences the sharpness of the phase transition from lead to lag near resonance, using your results from part (ii).