Question

What does galvanometer measure?

Answer 1

A galvanometer is an instrument which is connected in a circuit. A galvanometer can have various functions; it works on the basic principle of electromagnetic induction. Electromagnetic induction is the phenomenon of creating electric fields due to magnetic fields and vice versa.

Complete step-by-step solution:
A galvanometer is a device which works on the principle of electromagnetic induction. It is used to measure even the slightest flow of current. When the current flows through a galvanometer, its pointer gets deflected.
It consists of a metallic coil which is enclosed in a magnetic field made by two magnets in the shape of a horseshoe. When current flows through the coil, it generates its own magnetic field which gets intersected by the external magnetic field and the pointer attached to the coil gets deflected. A restoring force is developed in the coil due to which it returns to its original position.
A galvanometer can also be made to act as a voltmeter or an ammeter. If a resistance is connected in parallel to the galvanometer, it acts as a voltmeter while if a resistance is connected in series with a galvanometer, it acts as an ammeter.
Therefore, a galvanometer is used to measure the slightest flow of current in a circuit.

Note: The sensitivity of the galvanometer is the deflection produced per unit current flow. An ideal voltmeter has zero resistance that is why a resistance is connected in parallel to the galvanometer to reduce its resistance. An ideal ammeter has infinite resistance, so a resistance in series with a galvanometer increases its resistance.