Question

In a moving coil galvanometer, deflection of the coil is related to the electrical current $i$ by the relation

• A. $i\propto tan\theta$
• B. $i\propto \theta$
• C. $i\propto {\theta }^2$
• D. $i\propto \sqrt{\theta }$

Answer 1

The correct option is B $i\propto \theta$

Moving coil galvanometer is based on the fact that when a current carrying coil is placed in magnetic field it experiences a torque.
This torque is counter balanced by a spring system and deflection in that spring is proportional to current because it measure the torque which is proportional to the current.
$I=\frac{k\theta }{NBA}$