Question

A voltmeter has a resistance of g ohm and range of 1 volt. The value of resistance used in series to convert it into voltmeter of range n volt is

• A. ng
• B. (n-1)g
• C. g/n
• D. g/n-1

Answer 1

Answer: (B)

(n-1)g

$i=\frac{V}{G}$
$R_{eqv}=G+R$
So, taking same current.

$i=\frac{mV}{G+R}$

$\frac{V}{G}=\frac{nV}{G+R}$

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