Which instrument is specifically used to test the conductance of a transmission path in a non-energized circuit?

The correct answer, an ohmmeter, is specifically designed to measure the resistance of a circuit or component in a non-energized state. When testing the conductance of a transmission path, it evaluates how easily electricity can flow through the material, which is directly related to resistance. By determining the resistance, users can infer the conductance, as conductance is the reciprocal of resistance. This makes an ohmmeter the ideal tool for testing circuits that are not powered, ensuring accurate readings without the risk of electrical interference or hazards associated with energized circuits.

In contrast, an ammeter is used to measure current flowing through a circuit when in use and cannot provide accurate readings in a non-energized situation. A voltmeter is designed to measure voltage and requires the circuit to be powered to function properly. Lastly, a power meter measures the overall power consumption in a circuit when it is active, and similarly is not suitable for non-energized tests.