During a lab demonstration, two thermocouples were made by using copper-constantan wires. The junction diameter of one thermocouple is 1 mm, while the other is 0.2 mm. Initially, both thermocouples were held in a constant-temperature environment and both gave a temperature reading of 32°C. Then both thermocouples were released to a convective environment (still air) of 23°C. Due to the thermal capacity of the thermocouple junction, it took a while for the thermocouple to eventually reach 23°C.
This figure gives the recorded temperatures sensed by both thermocouples. If you are asked to select one of them to measure a transient temperature (dynamic change) in an experiment, which thermocouple would you prefer? Explain.