Final answer:
Using an ohmmeter, a device's resistance is measured when troubleshooting an electrical circuit. The component should be isolated and the circuit should not be live. The process is founded on Ohm's law.
Step-by-step explanation:
The correct answer is option Physics. When troubleshooting an electrical circuit, an ohmmeter is used to measure the resistance of a circuit component. If the ohmmeter is properly connected across a component and reads some value of resistance, it indicates that the component has a specific amount of resistance to the flow of electric current. The measuring should be done while the component is isolated from the rest of the circuit to ensure accuracy, as connecting an ohmmeter to a "live" circuit can damage the meter and produce incorrect readings. Understanding Ohm's law, which relates voltage (V), current (I), and resistance (R) in the formula V = IR, is fundamental when using an ohmmeter.
It is important to note that a voltmeter, which measures voltage, is connected in parallel with the component being measured and should have a high resistance relative to the tested device. This high resistance ensures that the voltmeter does not significantly alter the circuit. Conversely, an ammeter, which measures current, must be in series with the resistor. Ohm's law underlies the operations of both ohmmeters and voltmeters and is critical for ensuring accurate measurements in electrical circuits.