Question
State the use of galvanometer as a voltmeter.
✓
Answer
→A galvanometer can also be used as a voltmeter.
→For using galvanometer as a voltmeter it is connected in parallel with that component of the circuit.
→A galvanometer is a very sensitive device, so to avoid damage the current passing through it should be very small.
→For this a large resistance is connected in series with galvanometer, as shown in the figure.
→The resistance of voltmeter is $R _{ G }+ R$
But $R \gg R _{ G }$,
→So, $R _{ G }$ can be neglected as compare to R so the resistance of the voltmeter becomes $\approx R$.
→For using galvanometer as a voltmeter it is connected in parallel with that component of the circuit.
→A galvanometer is a very sensitive device, so to avoid damage the current passing through it should be very small.
→For this a large resistance is connected in series with galvanometer, as shown in the figure.
→The resistance of voltmeter is $R _{ G }+ R$
But $R \gg R _{ G }$,
→So, $R _{ G }$ can be neglected as compare to R so the resistance of the voltmeter becomes $\approx R$.
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