Question

How to convert a galvanometer into a voltmeter?

• A. By connecting high resistance in parallel with galvanometer.
• B. By connecting very low resistance in series with galvanometer.
• C. By connecting high resistance in series with galvanometer.
• D. none of these

Answer 1

The correct option is C By connecting high resistance in series with galvanometer.

The resistance of the voltmeter should be very large compared to the resistance across which the voltmeter is connected to measure the potential difference. Otherwise, the voltmeter will draw a large current from the circuit and hence the current through the remaining part of the circuit decreases. In such a case the potential difference measured by the voltmeter is very much less than the actual potential difference.
This can be only achieved by connecting a high resistance in series with galvanometer.