Which instrument is used to measure resistance?

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

Answer: (B)

Measuring resistance relies on determining how much current flows for a given voltage, so you need an instrument that can do that directly. An ohmmeter is designed for this purpose: it applies a small known current (or voltage) to the component and measures the resulting voltage (or current) to calculate resistance, giving you the resistance value directly. The voltmeter only measures voltage, the ammeter only measures current, and a wattmeter measures power, so none of them alone provides a direct resistance reading. For accurate results, isolate the component from the circuit before measuring, since other paths can distort the reading.