Question

100 mA current gives a full-scale deflection in a galvanometer of $2\Omega$ . The resistance connected with the galvanometer to convert it into a voltmeter to measure $5V$ is

• A. $98\Omega$
• B. $52\Omega$
• C. $50\Omega$
• D. $48\Omega$

Answer 1

The correct option is D $48\Omega$

Given, $i_g=0.1A,R_g=2\Omega$
and resistance added across the galvanometer to convert into voltmeter,
$R_L=5V$
So, $i_G(R_G+R_S)=R_L(i-i_G)i_G(R_G+R_S)=5V$
$0.1\times (2+R_s)=5(2+R_s)=50R_S=48\Omega$