Power At Resonance — the NEET Physics formula with its derivation, variables, validity constraints and worked solver.
Power at Resonance This formula applies specifically to an AC series RLC circuit when the driving frequency matches the natural resonant frequency (f = f r). Start with the general power formula: P = V rms I rms . Apply Ohm's Law for AC circuits: I rms = V rms / Z, where Z is the impedance. At resonance, the inductive and capacitive reactances cancel out, meaning the total impedance Z equals the resistance R (Z = R). Substitute Z = R into the power equation: P res = V rms (V rms / R) = V rms 2 / R. R > 0 V rms > 0 Assuming that the power dissipated is proportional to the square of the frequency (it is maximized at resonance). Confusing the maximum power (P res ) with the maximum current (I max ). Forgetting that the power formula uses RMS values, not peak values.