MP Board · Class 12 · Physics · Moving Charges and MagnetismWhat is the basic principle of a moving coil galvanometer?

The basic principle of a moving coil galvanometer is that a current-carrying coil placed in a uniform magnetic field experiences a deflecting torque. The magnitude of this magnetic torque is given by $\tau = NIAB \sin\theta$, where $N$ is the number of turns, $I$ is the current, $A$ is the area of the coil, $B$ is the magnetic field, and $\theta$ is the angle between the normal to the coil and the magnetic field. This torque twists a suspension wire until restoring torque balances it.