Which instrument is used to measure current in a conductor?

The instrument used to measure current in a conductor is an ammeter. An ammeter is specifically designed to measure the flow of electric current in amperes. It is connected in series with the circuit so that all the current flowing through the circuit passes through the ammeter. This allows for an accurate reading of the current.

A voltmeter measures voltage, and it is connected in parallel across a component or section of a circuit, which distinguishes its purpose from that of an ammeter. An ohmmeter is utilized to measure the resistance in a circuit, which involves measuring how much opposition there is to current flow, rather than measuring the current itself. A wattmeter, on the other hand, measures the power in a circuit, which is a function of both current and voltage. Therefore, the ammeter is the correct choice for measuring current specifically.