When a galvanometer is shunted by resistance S, then its current capacity increases n times. If the same galvanometer is shunted by another resistance S', then its current capcity will increase by n' is given by

Options

A. `(n+S)/S`
B. `(S(n-1)-S')/S'`
C. `((n+1)S)/S'`
D. `(S(n-1)+S')/S`

Answer

D

Explanation

Given: `i=ni_(g)thereforei_g/i=1/n=S/(S+G)thereforenS=S+Gtherefore S(n-1)=GthereforeS=G/(m-1)`In the second case, `S'=G/(n-1)thereforen'-1=G/S'thereforen'=G/S'+1=(G+S')/S'thereforen'=(S(n-1)+S')/(S')`.