Tennessee Wastewater Operator Practice Exam

Which of the following statements is not true concerning the operation of a magnetic flow meter?

1. It measures velocity of the flow

2. It requires a full pipe for accurate measurement

3. It operates partially full

4. It can handle turbulent flow

The correct answer is: It operates partially full

When discussing the operation of a magnetic flow meter, it's important to understand the parameters necessary for it to function accurately. The correct answer highlights that a magnetic flow meter typically requires a full pipe for accurate measurements. Magnetic flow meters operate on the principle of Faraday's law of electromagnetic induction, which states that a voltage is induced in a conductor moving through a magnetic field. For this principle to work effectively, the flow must completely fill the pipe. If the pipe is only partially filled, it can lead to erroneous readings and unreliable data, as the flow profile can become distorted. Indicating that a magnetic flow meter can operate reliably when partially full does not align with its requirements, which is why stating that it operates that way is not true. In contrast, the other options highlight aspects of the flow meter’s characteristics—such as its ability to measure flow velocity and handle turbulent flow—both of which are within its operational capabilities when the system is configured properly.