The deflection induced in the coil of the galvanometer per unit passage of electric current through it is known as current sensitivity.
Where, represents the strength of the magnetic field in which the coil is suspended; represents the area of the coil, represents the number of turns in the coil,and represents restoring torque per unit twist of the suspension string.
A galvanometer is a tool for detecting and measuring low currents.
It's commonly used to display tiny deflections in variable resistor and bridge circuits.
It's a sensitive instrument for measuring currents.
It can detect very low currents of a few microamperes or less.