Type of instrument used to measure electrical resistance?

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

Answer: (A)

An ohmmeter is the instrument designed to measure electrical resistance. It works by applying a small known current (usually from an internal battery) through the component and measuring the resulting voltage, or by applying a voltage and measuring the current; using Ohm’s law (R = V/I) it displays the resistance. This direct approach is what makes it specifically suited for resistance measurement, and you’ll typically use it with the component removed from the circuit to avoid parallel paths altering the reading. In contrast, a voltmeter is meant to measure voltage, an ammeter measures current, and a galvanometer is a sensitive current detector used in various meters rather than a direct resistance measuring tool. Digital meters often include an ohmmeter function, but the principle remains the same: it injects current and reads the resistance.