Question
Physics Question on Moving charges and magnetism
To convert a galvanometer into a voltmeter one should connect a : -
High resistance in series with galvanometer
Low resistance in series with galvanometer
High resistance in parallel with galvanometer
Low resistance in parallel with galvanometer
High resistance in series with galvanometer
Solution
Key Idea: A galvanometer has its own resistance low but a voltmeter must have high resistance. A voltmeter indeed is a modified form of a pivoted coil galvanometer. Since the resistance of coil of galvanometer of its own is low, its resistance is to be increased as is a necessary condition for a voltmeter. For this an appropriate high resistance should be connected in series with the galvanometer as shown. Note: The resistance of an ideal voltmeter should be infinite.