What is one limitation of thermocouples regarding temperature measurement?

The limitation of thermocouples regarding temperature measurement primarily concerns their accuracy issues. While thermocouples are widely used and can measure a broad range of temperatures, they may not always provide precise readings. Factors such as the type of materials used in the thermocouple junctions, the calibration of the device, and environmental conditions can all impact the accuracy of the temperature readings. This means that while thermocouples are versatile and useful for many applications, users must be aware that their measurements can have some degree of error compared to other temperature measurement methods.

Other options address different aspects of thermocouples but do not encapsulate the essence of this limitation as clearly as accuracy issues do. For instance, while it is true that thermocouples perform optimally across various temperature ranges, they still cover a significant range, making the first option less of a limitation in practical applications. The option regarding measuring only liquid temperatures is incorrect, as thermocouples can measure solid and gas temperatures as well. Lastly, cost-prohibitive use does not accurately describe thermocouples, as they are generally regarded as affordable temperature sensors compared to some other technologies.