Which device is used to measure electrical current?

The device used to measure electrical current is the ammeter. An ammeter is specifically designed to measure the flow of electric current in a circuit, typically measured in amperes (A). It can be connected in series with the circuit to provide an accurate measurement of the current flowing through that particular part of the circuit.

In contrast, a voltmeter measures the voltage across two points in a circuit, while a wattmeter measures the power (in watts) consumed in a circuit, combining both voltage and current measurements. An ohmmeter is used to measure resistance in ohms. Thus, the ammeter is the dedicated instrument for current measurement, making it the correct answer.