A 30 mm diameter copper sphere and a 30 mm copper cube are both heated in a furnace to 923 K. They are then annealed in an air at 378K. If the external heat transfer coefficient h is 80 W/m2.K in both...

Extracted text: A 30 mm diameter copper sphere and a 30 mm copper cube are both heated in a furnace to 923 K. They are then annealed in an air at 378K. If the external heat transfer coefficient h is 80 W/m2.K in both cases, what is the temperature of the sphere and of the cube at the end of 6 minutes