Question:
A moving coil galvanometer allows a full scale current of $10^{-4} \mathrm{~A}$. A series resistance of $2 \mathrm{M} \Omega$ is required to convert the above galvanometer into a voltmeter of range $0-5 \mathrm{~V}$. Therefore the value of shunt resistance required to convert the above galvanometer into an ammeter of range $0-10 \mathrm{~mA}$ is:
Correct Option: , 4
Solution:
(4) $\quad \mathrm{v}=\mathrm{i}_{\mathrm{g}}(\mathrm{R}+\mathrm{G})$
$\Rightarrow 5=10^{-4}\left(2 \times 10^{6}+\mathrm{x}\right)$
$\mathrm{x}=-195 \times 10^{4} \Omega$