Athermocouple detector has characteristics such that the minimum input power necessary to produce an S/N ratio of unity is 3×10-6 W.A2-in-diameter optical system collects the input thermal radiation and focuses it on the thermocouple. The optical-thermocouple system is to be used to measure the temperature of a 2-in black sphere 6 ft away. The thermocouple bead is maintained at a temperature of 70?F. Estimate and plot the uncertainty in the temperature measurement as a function of the temperature of the sphere.