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MHT CET · Physics · Current Electricity

The range of voltmeter of resistance ' G ' \(\Omega\) is ' V ' volt. The resistance required to be connected in series with it in order to convert it into a voltmeter of range ' \(n V\) ' volt, will be

  1. A \((\mathrm{n}-1) \mathrm{G}\)
  2. B \(\mathrm{G} / \mathrm{n}\)
  3. C nG
  4. D \(\frac{\mathrm{G}}{\mathrm{n}}-1\)
Verified Solution

Answer & Solution

Correct Answer

(A) \((\mathrm{n}-1) \mathrm{G}\)

Step-by-step Solution

Detailed explanation

Here, The range of a voltmeter of resistance G is V volt. Let, I be the current thruogh it then
\(\mathrm{G}=\frac{\mathrm{V}}{\mathrm{I}} \ldots\) (1)
Now to convert it into voltmeter of range nV , the required resistance will be,
\(\mathrm{R}=\frac{\mathrm{nV}}{\mathrm{I}}=\mathrm{nG}\) (from (1))
Hence, the resistance to be added in series is
\(\mathrm{R}-\mathrm{G}=\mathrm{nG}-\mathrm{G}=(\mathrm{n}-1) \mathrm{G}\)
The resistance \((\mathrm{n}-1) \mathrm{G}\) is to be connected in series with voltmeter of range V in order to convert it into a voltmeter of range nV volt,