question_answer

A galvanometer acting as a voltmeter will have:                                                      [AIPMT (S) 2004]

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

Correct Answer: B

Solution :

[b] Key Idea: To work as voltmeter, the resistance of galvanometer should be high. A voltmeter indeed is a modified form of a pivoted coil galvanometer. Since, the resistance of coil of galvanometer of its own is low, hence to convert a galvanometer into a voltmeter, its resistance is to be increased. For this an appropriate high resistance is joined in series with the galvanometer as shown in figure

The value of this resistance to be connected depends on the range of the voltmeter.

Note:    A voltmeter is always connected in parallel in an electric circuit.