Plant Operation Practice Test

What do thermocouples measure?

1. Pressure

2. Humidity

3. Temperature

4. Flow rate

The correct answer is: Temperature

Thermocouples are specifically designed to measure temperature. They function on the principle of thermoelectricity, which involves the generation of a voltage when two different metals are joined together at different temperatures. When the junction of the dissimilar metals is exposed to heat, it produces a voltage that can be correlated to the temperature at that junction. This makes thermocouples highly effective for a wide range of applications in various industries, including manufacturing, aerospace, and chemical processing, where accurate temperature measurements are critical for process control and safety. The other options pertain to different measurement devices; for instance, pressure is typically measured by pressure transducers or gauges, humidity is commonly measured using hygrometers, and flow rate is assessed by flow meters. Each of these instruments has its specific operating principles and applications that do not overlap with the temperature-sensing capabilities of thermocouples. This specificity of function is what makes thermocouples uniquely suited for temperature measurement.