What instrument is used to measure electric current?

• A. Voltmeter
• B. Ohmmeter
• C. Galvanometer
• D. Ammeter

Answer: (D)

Measuring electric current means checking how much electric charge passes a point each second, which is measured in amperes. The tool built for this purpose is the ammeter. It’s placed in series with the circuit so all the current flows through it, and it has very low internal resistance so it doesn’t significantly alter the current or the voltage in the rest of the circuit.

In contrast, a voltmeter measures voltage (potential difference) and is wired in parallel across a component; it has high resistance to avoid drawing current from the circuit. An ohmmeter measures resistance by applying a small current and reading the resulting voltage, typically used when the circuit is off. A galvanometer is a very sensitive current detector that can indicate the presence and direction of small currents, and its mechanism forms the movement inside many meters; to measure larger currents reliably in a circuit, it’s usually used with a shunt or converted into an ammeter.

So, the instrument used to measure electric current is the ammeter.