Question

$R_1=2\Omega ,R_2=2\Omega ,R_3=3\Omega$ connected to a battery of emf 6V as shown . If the resistance of the voltmeter is $2\Omega$. Find the reading in the voltmeter

Answer 1

From given circuit -

Equivalent resistance $=R=\frac{R_1{R}_v}{R_1+R_v}+R_2+R_3$ where $R_v=2\Omega$=resistance of voltmeter

$R=\frac{2\times 2}{2+2}+2+3=6\Omega$

Current in circuit$=I=\frac{E}{R}=\frac{6}{6}=1A$

Potential difference across combination of $R_1$ and voltmeter is

$V=I\times 1$ since $1\Omega$ is equivalent resistance of $R_1$ and voltmeter

$⟹V=1V$