13. The temperature of a experimental heated enclosure is being ramped up from 80 to 450F at the rate of 20F/min. A thermocouple, embedded in a thermowell for protection, is being used to monitor the oven temperature. The thermocouple has a time constant of 6s. (a) At t=10min, what is the difference between the actual temperature and the temperature indicated by the thermocouple? What is it at 60min ? (b) When the thermocouple indicates 450F, the heater will begin to modulate and maintain the temperature at the desired 450F. What is the actual oven temperature when the thermocouple first indicates 450F