Define current sensitivity and voltage sensitivity of a galvanometer.

Current sensitivity : It is defined as the deflection of coil per unit current flowing in it.

Voltage sensitivity : It is defined on the deflection of coil per unit potential difference across its ends.

When number of turns N is doubled then the current sensitivity ∝ N is doubled;

but at the same time the resistance of galvanometer coil G will also be doubled so voltage sensitivity Sv ∝ N / Gwill remain unchanged;

Hence, increasing current sensitivity does not necessarily increase the voltage sensitivity.