Question

The range of a voltmeter of resistance $G\Omega$ is V volt. The resistance required to be connected in series with it in order to convert it into a voltmeter of range nV volt, will be

• A. $(n-1)G$
• B. $\frac{G}{n}$
• C. $nG$
• D. $\frac{G}{(n-1)}$

Answer 1

The correct option is A $(n-1)G$

Here, The range of a voltmeter of resistance $G$ is V volt. Let, $I$ be the current thruogh it then

$G=\frac{V}{I}$.................................$\left(1\right)$

Now to convert it into voltmeter of range $nV$, the required resistance will be,

$R=\frac{nV}{I}=nG$ ..............................$($from $\left(1\right))$

Hence, the resistance to be added in series is

$R-G=nG-G=(n-1)G$

The resistance $(n-1)G$ is to be connected in series with voltmeter of range $V$ in order to convert it into a voltmeter of range $nV$ volt,