Question

A galvanometer has a resistance $50\,\Omega$ . A resistance of $5\,\Omega$ is connected parallel to it. Fraction of the total current flowing through galvanometer is

• A. $\frac{1}{10}$
• B. $\frac{1}{11}$
• C. $\frac{1}{50}$
• D. $\frac{2}{15}$

Answer 1

Answer: (B)

$\frac{1}{11}$

Answer 2

The galvanometer $G$ and shunt $S$ is connected in parallel,
hence potential difference is the same.
$\therefore i_{g} \times G=\left(i-i_{g}\right) \times S$
$\Rightarrow \frac{i_{g}}{i-i_{g}}=\frac{S}{G}=\frac{5}{50}=\frac{1}{10}$
$\Rightarrow 10 i_{g}=i-i_{g}$
$\Rightarrow 11 i_{g}=i$
$\Rightarrow \frac{i_{g}}{i}=\frac{1}{11}$