Question

An LCR circuit contains resistance of 110 Ω and a supply of 220 V at 300 rad/s angular frequency. If only capacitance is removed from the circuit, current lags behind the voltage by 45°. If on the other hand, only inductor is removed the current leads by 45° with the applied voltage. The rms current flowing in the circuit will be ______.

विकल्प

• 1.5 A

• 1 A

• 2 A

• 2.5 A

Answer 1

An LCR circuit contains resistance of 110 Ω and a supply of 220 V at 300 rad/s angular frequency. If only capacitance is removed from the circuit, current lags behind the voltage by 45°. If on the other hand, only inductor is removed the current leads by 45° with the applied voltage. The rms current flowing in the circuit will be 2 A.

Explanation:

cos 45° = `"R"/"X"_"L"`    ...(i)

cos 45° = `"R"/"X"_"C"`    ...(ii)

So, from (i) & (ii) we get X_L =X_c i.e. circuit in resonance.

LCR circuit is in resonance, behaves as resistive circuit.

∴ `"I"_"rms" = "V"_"rms"/"R" = 220/110 = 2 "A"`