Question

In the circuit shown in the figure reading of voltmeter is $V_{1}$ when only $S_{1}$ is closed, the reading of voltmeter is $V_{2}$ when only $S_{2}$ is closed and the reading of voltmeter is $V_{3}$ when both $S_{1}$ and $S_{2}$ are closed. Then:-

• A. $V_{3}>V_{2}>V_{1}$
• B. $V_{2}>V_{1}>V_{3}$
• C. $V_{3}>V_{1}>V_{2}$
• D. $V_{1}>V_{2}>V_{3}$

Answer 1

Answer: (B)

When only $S_{1}$ is closed $V_{1}=\frac{3}{4}E=0.75E$
When only $S_{2}$ is closed $V_{2}=\frac{6}{7}E=0.86E$
and when both $S_{1}$ and $S_{2}$ are closed combined resistance of $6R$ and $3R$ is $2R$
$\therefore V_{3}=\left(\frac{2}{3}\right)E=0.67E\Rightarrow V_{2}>V_{1}>V_{3}$