Physics | MHT CET 2019 | Discussion Page

The range of an ammeter of resistance 'G' can be increased from 'l' to 'nl' by connecting

A) a series resistance of $\frac{G}{n+1}\Omega$

B) a shunt of $\frac{G}{n-1}\Omega$

C) a shunt of $\frac{G}{n+1}\Omega$

D) a series resistance of $\frac{G}{n-1}\Omega$

Option B

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

whose value is given by

$R=\left(\frac{l_{g}}{l-l_{g}}\right) G\Omega$ .......(i)

To increase the range from l to nl , the current passing through it is l= nl_g

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

$R=\left(\frac{l_{g}}{nl_{g}-l_{g}}\right) G$

= $\frac{G}{n-1}\Omega$

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