A voltmeter has a resistance `G` and range `V`. Calculate the resistance to be used in series with it to extend its range to `nV`.

Options

A. `nG`
B. `(n - 1)G`
C. `G//m`
D. `G//(n - 1)`

Answer

B

Explanation

We know that
`R = (V)/(I_(g)) - G`
The voltmeter gives the full-scale deflection for potential difference `V`. Its resistance is `G`. Hence, `I_(g) = (V//G)`. Given that
`V = nV`. Therefore,
`R(nV)/(V//G) - G = (n- 1) G`