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MHT CET · Physics · Alternating Current

With gradual increase in frequency of an a.c. supply, the impedance of an LCR series circuit

  1. A increases.
  2. B decreases.
  3. C remains constant
  4. D first decreases, becomes minimum and then increases.
Verified Solution

Answer & Solution

Correct Answer

(D) first decreases, becomes minimum and then increases.

Step-by-step Solution

Detailed explanation

We know
\(\mathrm{X}_{\mathrm{L}}=\mathrm{L} \omega\) and \(\mathrm{X}_{\mathrm{C}}=\frac{1}{\mathrm{C} \omega}\)
\(\Rightarrow\) When the frequency increases, \(\mathrm{X}_{\mathrm{L}}\) increases and \(\mathrm{X}_{\mathrm{C}}\) decreases.
\(\therefore \quad\) The impedance of an LCR series circuit decreases at first, becomes minimum and then increases.