Q138 / 150 · MHT CET 2019 (Shift 2) · Physics

The range of an ammeter of resistance ‘G’ can be increased from ‘I’ to ‘nI’ by connecting

Solution

The range of an ammeter can be increased by connecting a shunt or parallel resistance to it, whose value is given by

R = (\frac{l_{g}}{l - l_{g}}) G Ω

To increase the range from l to

n l,

the current passing through it is l =

n l_{g}

Using this value in Eq. (i), we get

R = (\frac{l_{g}}{n l_{g} - l_{g}}) G

= \frac{G}{(n - 1)} Ω

Hence, the correct answer is option: 'B'.