Question

The deflection in a moving coil galvanometer is reduced to half when it is shunted with a $40\, \Omega$ coil. The resistance of the galvanometer is

• A. $80\, \Omega$
• B. $40 \, \Omega$
• C. $20\, \Omega$
• D. $15 \, \Omega$

Answer 1

Answer: (B)

$40 \, \Omega$

Answer 2

We know, $\frac{I_{G}}{I}=\frac{1}{2}$
$\frac{S}{G+S}=\frac{1}{2}$
$\frac{I_{G}}{I}=\frac{40}{G+40}= \frac{1}{2}$
$G=40\, \Omega$