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Concepts Of Physics MCQ Edition [Volume 2]PhysicsAlternating Current

An inductor, a resistor, and a capacitor are connected in series with an AC source. When the frequency of the source is slightly increased from a very low initial value, the reactance

Options

  1. Aof the inductor increases
  2. Bof the capacitor increases
  3. Cof the resistor increases
  4. Dof the circuit increases

Correct answer

A. of the inductor increases

Step-by-step solution

The reactance of an inductor is given by X_L = L = 2 f L , where f is the frequency of the AC source. When the frequency f is increased, the inductive reactance X_L increases. The reactance of a capacitor is given by X_C = 1 C = 1 2 f C . When the frequency f is increased, the capacitive reactance X_C decreases. The resistance R of a resistor is independent of the frequency of the AC source. At very low frequencies, the circuit is highly capacitive ( X_C > X_L ). The magnitude of the net reactance of the circuit is

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