A series LCR circuit with R = 20Ω, L = 1.5 H and C = 35 μF is connected to a variable-frequency 200 V A.C. 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?

Question

Philoid · Accepted Answer

Given:

R = 20 _Ω

L = 1.5 H

C = 35 μF = 35 × 10^-6F

Voltage supplied V = 200 V

The diagram given is:

Impedance of the circuit can be calculated as follows:

At resonance condition i.e. when ωL = 1/ωC

Z = R = 20 Ω

Current is given by the relation

I = V/R

I = 200V /20Ω

⇒ I = 10A

Therefore, the average power transferred to the circuit in one complete cycle can be calculated as follows:

Power = VI

Power = 200V × 10A

Power = 2000 W.