Q. A galvanometer has a resistance of $25\ ohm$ and a maximum of $0.01\ A$ current can be passed through it. In order to change it into an ammeter of range $10\ A,$ the shunt resistance required is
A) $5/999\ ohm$
B) $10/999\ ohm$
C) $20/999\ ohm$
D) $25/999\ ohm$
Explanation
(d) $i_{g} = i\frac{S}{G + S} \Rightarrow 0.01 = 10\frac{S}{25 + S}$
$\Rightarrow 1000S = 25 + S \Rightarrow S = \frac{25}{999}\Omega$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.