question_answer

                To convert a galvanometer into a voltmeter, one should connect a:

A)                                                            high resistance in series with galvanometer        

B)                 low resistance in series with galvanometer

C)                 high resistance in parallel with galvanometer

D)                 low resistance in parallel with galvanometer

Correct Answer: A

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.