It is desired to measure a temperature differential of 15C using copper-constantan thermocouples at a temperature level of 150C. A millivolt recorder is available for the emf measurement which has an uncertainty of 0.04mV. Precision thermocouple wire is available, which may be assumed to match the characteristics in Table 8.3 exactly. How many junction pairs in a thermopile must be used in order that the uncertainty in the temperature differential measurement does not exceed 0.1C ? Neglect all errors due to heat transfer. (5 points) TwT=EwE,150C 0.05mV