Q. A microammeter has a resistance of 100 $\Omega$ and full scale range of $50\mu$ A. It can be used as a voltmeter of as a higher range ammeter provided a resistance is added to it. Pick the correct range and resistance combinations
A) 50 V range with 10 k $\Omega$ resistance in series
B) 10 V range with 200 k $\Omega$ resistance in series
C) 10 mA range with 1 $\Omega$ resistance in parallel
D) 10 mA range with 0.1 $\Omega$ resistance in parallel
Explanation
(b) To convert a galvanometer into a voltmeter, a resistance $R = \frac{V}{i_{g}} - G$ is connected in series of it.
To convert galvanometer into an ammeter, a resistance $S = \ i_{g}G/(i - i_{g})$ is to be connected in parallel of galvanometer.
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.