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The potential differences across the resistance, capacitance and inductance are 80 V, 40 V and 100 V respectively in an LCR circuit. The power factor of this circuit is

Asked in NEET 2016 Phase-II · Power factor

Answer: (3) 0.8

Step-by-step solution

The inductor and capacitor voltages oppose each other, so the supply voltage is

V=√V_R²+(V_L-V_C)²=√80²+(100-40)²=√6400+3600=100 V.

The power factor is cos φ=R/Z, and since the same current flows through every

element that ratio equals (V_R)/V.

cos φ=(80)/(100)=0.8.

Why the other options are wrong

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