Multiple choice general knowledge

How does a coil react to AC?

  1. As the frequency of the applied AC increases, the reactance decreases

  2. As the frequency of the applied AC increases, the reactance increases

  3. As the amplitude of the applied AC increases, the reactance decreases

  4. As the amplitude of the applied AC increases, the reactance increases
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

In an inductor, reactance increases with frequency because the rate of change of current increases, causing greater back EMF. The formula is XL = 2πfL, where f is frequency and L is inductance. Amplitude does not affect reactance, only frequency does. This is why inductors block high-frequency AC signals.

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