A moving coil galvanometer has a coil with 175 turns and area $1 \mathrm{~cm}^2$. It uses a torsion

Question

A moving coil galvanometer has a coil with 175 turns and area $1 \mathrm{~cm}^2$. It uses a torsion band of torsion constant $10^{-6} \mathrm{~N}-\mathrm{m} / \mathrm{rad}$. The coil is placed in a magnetic field $B$ parallel to its plane. The coil deflect by $1^{\circ}$ for a current of 1 mA . The value of $B$ (in Tesla) is approximately

Professor PC Thomas Classes · Answer

$NIAB = k	heta \implies B = \frac{k	heta}{NIA} = \frac{10^{-6} 	imes (\pi/180)}{175 	imes 10^{-3} 	imes 10^{-4}} \approx 10^{-3} 	ext{ T}$.