Cathodic Protection Tester Practice Exam

What does a voltmeter measure in a structure?

1. Electrolyte resistance

2. Voltage between the structure and electrolyte

3. Current flow

4. Power consumption

The correct answer is: Voltage between the structure and electrolyte

A voltmeter measures the voltage difference between two points in an electrical circuit, and in the context of cathodic protection, it typically measures the voltage between a structure, such as a pipeline or a storage tank, and the surrounding electrolyte, such as soil or water. This measurement is critical for evaluating the effectiveness of cathodic protection systems, as it helps determine whether the structure is adequately protected from corrosion. Understanding the voltage between the structure and the electrolyte is essential for professionals in the field because it indicates the level of protection being provided. A negative reading usually suggests that the cathodic protection system is effectively protecting the structure, as it indicates that the potential of the structure is lower than that of the surrounding electrolyte, which helps prevent corrosion. In contrast, the other options do not accurately reflect what a voltmeter measures in this context. Electrolyte resistance pertains to the resistive properties of the medium surrounding the structure and is typically measured with an ohmmeter. Current flow is measured in amperes and is related to the flow of electrons, which is monitored by an ammeter, and power consumption indicates the amount of energy used by a device and is measured in watts, neither of which relates to the voltage measurement provided by a voltmeter in