Question

A voltmeter has range $0\to V$ with a series resistance R. With a series resistance 2R, the range is $0\to V$'. The correct relation between v and v' is

• A. $v^1=2v$
• B. $v^1>2v$
• C. $v^1<2v$
• D. $v^1>>2v$

Answer 1

The correct option is A $v^1=2v$

$V=i_g(G+S)$
$V=i_g(G+R)$
&
$V^{\prime }=i_g(G+2R)$
$\therefore V^{\prime }=2V$