Question

Statement I: Chock coil is preferred over a resistor to adjust current in an $AC$ circuit.
Statement II: Power factor for inductance is zero.

• A. If both statements are true and statement II is the correct explanation of statement $I$.
• B. If both statements are true but statement II is not the correct explanation of statement $I$.
• C. If statement $I$ is true but statement II is false.
• D. If both statements are false.

Answer 1

Answer: (A)

If resistor is used in controlling AC supply, electrical energy will be wasted in the form of heat energy across the resistance wire. However, AC supply can be controlled with choke without any wastage of energy. This is because power factor $(\cos \phi)$ for resistive circuit is unity and is zero for an inductive circuit. $[P=E I \cos \phi]$