With gradual increase in frequency of an a.c. supply, the impedance of an LCR series circuit
With gradual increase in frequency of an a.c. supply, the impedance of an LCR series circuit
increases.
decreases.
remains constant
first decreases, becomes minimum and then increases.
Solution
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.