NEET-XII-Physics
07: Alternating Current
- #9A series LCR circuit with R = 20 ``\Omega``, L = 1.5 H and C = 35 μF is connected to a variable-frequency 200 V ac supply. When the frequency of the supply equals the natural frequency of the circuit, what is the average power transferred to the circuit in one complete cycle?
Ans : At resonance, the frequency of the supply power equals the natural frequency of the given LCR circuit.
Resistance, R = 20 ``\Omega``
Inductance, L = 1.5 H
Capacitance, C = 35 μF = 30 × 10-6 F
AC supply voltage to the LCR circuit, V = 200 V
Impedance of the circuit is given by the relation,
At resonance,
Current in the circuit can be calculated as:
Hence, the average power transferred to the circuit in one complete cycle= VI
= 200 × 10 = 2000 W.