What is the function of a galvanometer?

A galvanometer is specifically designed to detect and measure small electric currents. Its operating principle relies on the interaction of a magnetic field with a current-carrying conductor, which causes a needle to deflect on a scale to indicate the strength of the current flowing through it.

This function is crucial in various applications, such as in laboratory experiments or in old electric measuring devices, where it's necessary to measure low currents precisely. The ability of a galvanometer to indicate even the smallest changes in current makes it an essential tool in both scientific research and electrical engineering.

While the other options pertain to different aspects of electrical measurement, the galvanometer's primary purpose aligns most closely with measuring small currents, distinguishing it from instruments meant for larger current measurements, voltage levels, or resistance.