Question

Moving Coil Galvanometer —

Answer 1

Moving Coil Galvanometer —

It is an instrument used for detection and measurement of small currents.

Principle of a moving coil galvanometer : When a current carrying coil is placed in a magnetic field, it experiences a torque.

In moving coil galvanometer the current $I$ passing through the galvanometer is directly proportional to its deflection $(\theta)$.

$I \propto \theta \text { or, } I=\mathrm{G} \theta .$

where $G=\frac{k}{N A B}=$ galvanometer constant,

$A=$ area of coil, $N=$ number of turns in the coil, $B=$ strength of magnetic field, $k=$ torsional constant of the spring i.e. restoring torque per unit twist.