Question

A galvanometer acting as a voltmeter will have
A. a high resistance in parallel with its coil
B. a high resistance in series with its coil
C. a low resistance in parallel with its coil
D. a low resistance in series with its coil

Answer 1

Hint: A device that measures the difference in electric potential between two locations in an electric circuit is a voltmeter. A galvanometer acting as a voltmeter is to be treated as a voltmeter as it will show the same readings as a voltmeter. Only the resistance of the galvanometer may vary from a voltmeter.

Complete step by step solution:
A galvanometer is a device that works with a point deflecting towards an electric field in a magnetic field. The galvanometer is constructed using a point deflecting scale (galvanometer) and resistance in a wire or coil. A voltmeter is created when the galvanometer and resistance are connected in a series. So, a galvanometer acting as a voltmeter will have high resistance compared to a normal galvanometer.

When the current is passed through the voltmeter in the coil the point is deflected towards the current flowing. As the resistance and galvanometer are connected in series it will overall have very high resistance so for the proper flow of current a galvanometer should have low resistance.

So, option B is the correct answer i.e, a galvanometer acting as a voltmeter will have high resistance in series with its coil is the required solution.

Additional Information: When the different resistances are connected in series, they are added directly or arithmetically, and when they are connected in parallel the resistances are added harmonically.

Note: As a voltmeter is created when the galvanometer and resistance are connected in a series, if a galvanometer is acting as a voltmeter then it will have high resistance compared to a normal galvanometer. A galvanometer also has a resistance so it should be connected with another resistance of the coil to create a high resistance.