Question

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

• A. $\frac{(n+1)S}{S'}$
• B. $\frac{S(n-1)+S'}{S'}$
• C. $\frac{n+S}{S'}$
• D. $\frac{S(n-1)-S'}{S'}$

Answer 1

Answer: (B)

$\frac{S(n-1)+S'}{S'}$

Answer 2

Using the relation $S=\frac{G}{(n-1)}$ $\Rightarrow$ $G=S(n-1)$ and $S'\frac{G}{(n'-1)}$ $\Rightarrow$ $n'=\frac{G+S'}{S'}$ $\therefore$ $n'=\frac{S(n-1)+S'}{S'}$