(a) Briefly explain how a galvanometer is converted into a voltmeter.
(b) A voltmeter of a certain range is constructed by connecting a resistance of in series with a galvanometer. When the resistance of
is connected in series, the range gets halved. Find the resistance of the galvanometer.
(a) A galvanometer can be converted into Voltmeter by connecting a high-value resistance R in series with the coil of the galvanometer. The value of (R) is related to the maximum voltage (V) to be measured as
(b) To determine the resistance of the galvanometer :
We have,
Where, Resistance of a galvanometer
Current in galvanometer
Now, According to the Question,
therefore,
Hence,