Question

A galvanometer has resistance G and Current I_g produced full scale deflection. $S_1$ is the value of the shunt which converts it into an ammeter of range 0 - I and $S_2$ is the value of shunt for the range 0 - 2I. The ratio
of $S_1$ to $S_2$ is

• A. $\frac{1}{2}\left(\frac{l-l_g}{1l-l_g}\right)$
• B. $\left(\frac{2l-l_g}{l-l_g}\right)$
• C. $\frac{1}{2}$
• D. $2$

Answer 1

The correct option is B $\left(\frac{2l-l_g}{l-l_g}\right)$

$S_1=\frac{G{l}_g}{l-l_g}$ and $S_2=\frac{G{l}_g}{2l-l_g}$. Hence $\frac{S_1}{S_2}=\frac{2l-l_g}{1-l_g}$