Question

In $R-L-C$ series circuit, the potential differences across each element is $20V$. Now the value of the resistance alone is doubled, then $P.D.$ across $R,L$ and $C$ respectively

• A. 20 V, 10 V, 10 V
• B. 20 V, 20 V, 20 V
• C. 20 V, 40 V, 40 V
• D. 10 V, 20 V, 20 V

Answer 1

Answer: (A)

Given, the potential difference across each element is same i.e., $20V,so$, the circuit is at resonance and we have
$V=V_R=20V$
If the value of $R$ is doubled, then value of $/$ reduced to half
$\therefore V_L=V_C=\frac{I{X}_L}{2}=\frac{I{X}_C}{2}=\frac{20}{2}=10V$
$(\because$ circuit is at resonance $)$
and $V_R=V=20V$