What is the end of the thermocouple that is inserted into the process called?

The end of the thermocouple that is inserted into the process is called the measuring junction. This part of the thermocouple is where the temperature measurement takes place. When the measuring junction is exposed to the temperature of the process, it creates a voltage difference due to the thermoelectric effect, which is then used to determine the temperature.

In contrast, the reference junction, which is not the correct choice, is part of the thermocouple system that refers to the point where the thermocouple wires are connected to a reference temperature, typically at a known temperature like that of ice water or a room temperature setting. The bimetallic junction, also not the answer, refers to a component in temperature measurement using bimetallic strips, while the resistance junction is a term that does not commonly pertain to thermocouples used for temperature measurement. Thus, the measuring junction is essential for accurate readings and is fundamental to the functionality of a thermocouple.