MP Board · Class 12 · Physics · Alternating CurrentExplain what a Choke Coil is and why it is preferred over a resistor to control current in an AC circuit.

A choke coil is a high-inductance and low-resistance induction coil used to control alternating current in an AC circuit without significant loss of electrical energy. When a choke coil with negligible resistance ($R \approx 0$) is used, the phase difference between voltage and current becomes nearly $90^\circ$. Consequently, the average power loss $P_{avg} = V_{rms} I_{rms} \cos(90^\circ) = 0$. In contrast, using an ordinary resistor causes substantial electrical energy dissipation as heat ($I^2R$), making the choke coil far more energy-efficient.