A copper sphere 2.5 cm in diameter is used as a slug-type heat-flux meter. A thermocouple is attached to the interior and the transient temperature recorded when the sphere is suddenly exposed to a convection environment. Plot the time response of the system for sudden exposure to an environment with h = 570 W/m2 · ?C. Assume the sphere is initially at 95?C and the environment temperature remains constant at 35?C. What is the time constant of this system?