A galvanometer measures current which passes through it. A galanometer can measure typically carrent of order of mA. To be able to measure currents of the order of amperes of main current, a shunt resistance 'S' is connected in parallel with galvanometer.

If resistance of galavonometer is `10Omega` and maximum current `i_(g)` is 10mA then the shunt resistance required so that the main current 'I' can be upto 1A is (in `Omega`)

Options

A. `(99)/(10)`
B. `(10)/(99)`
C. 990
D. `(99)/(1000)`

Explanation

Potential difference across galvanometer = Potential diffenence across S.
`rArr i_g.G=(I-i_g).S`
`rArr 10xx10^(-3).10=(1-10xx10^(-3)).S rArr R_S=10^(-1)/(1-10^(-2))=10/99Omega`