An ammeter has resistance `R_(0)` and range l what resistance should be connected in parallel with it to increase its range by nl ?

Options

A. `R_(0)/(n-1)`
B. `R_(0)/(n+1)`
C. `R_(0)/n`
D. none of these

Answer

C

Explanation

Given `i_(g)=iG=R_(0),I=ni+i=(n+1)i`
`therefore` shunt `S=(i_(g)G)/(i-i_(g))=(IR_(0))/(n+1)I -i=(r_(0))/(n)`