Question 297: AC fundamentals

Question

Which one of the following graph represent correctly the variation of impedance $(\mathrm{Z})$ of a series LCR circuit with the frequency $(v)$ of applied a.c.?
![](https://app-content.cdn.examgoal.net/fly/@width/image/jaoe38c1m4uwc7ke/68d34572-d124-4c85-99d6-b7f2bee76e8b/4048b6e0-bdcc-11ef-947d-73ffb5e95f68/file-jaoe38c1m4uwc7kf.png?format=png)

Accepted Answer

$\mathrm{Z}=\sqrt{\mathrm{R}^2+\left(2 \pi v L-\frac{1}{2 \pi v C}\right)^2}$
From above equation at $v=0 \Rightarrow Z=\infty$
When $v=\frac{1}{2 \pi \sqrt{\mathrm{LC}}}$ (resonant frequency)
$\Rightarrow \mathrm{Z}=\mathrm{R}$
For $v>\frac{1}{2 \pi \sqrt{L C}} \Rightarrow Z$ starts increasing.
i.e., for frequency $0-v_r, Z$ decreases and for $v_r$ to $\infty, \mathrm{Z}$ increases. This is justified by graph (B).

Answer

A

Answer

B

Answer

C

Answer

D

AC fundamentals

Which one of the following graph represent correctly the variation of impedance (\mathrm{Z}) of a series LCR circuit with the frequency (v) of applied a.c.?

Choose the correct answer: