Q. A moving coil galvanometer gives full scale deflection, when a current of 0.005 A is passed through its coil. It is converted into a voltmeter reading upto 5V by using an external resistance of 975 $\Omega$. What is the resistance of the galvanometer coil?
A) 30 $\Omega$
B) 25 $\Omega$
C) 50 $\Omega$
D) 40 $\Omega$
Explanation
(b) Here, $i_{g} = 0.005\ $A; $V = 500\ $volt;
$R = 965\ \Omega$, G =?
$R = \frac{V}{i_{g}} - \ G$
Or $G\ = \frac{V}{i_{g}} - R = \frac{5}{0.005} - 975 = 25\Omega$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.