THE WALL OF A STOVE OVEN (as shown in the figure), WHICH IS MADE OF TWO THIN LAYERS OF STEEL (AS SUPPORT, BUT DOES NOT OFFER RESISTANCE TO THE PASSAGE OF HEAT), WHICH CONTAINS A FIBERGLASS LAYER AND ANOTHER OF REFRACTORY BRICK AS INSULATORS INSIDE THEM (S=1 m). THE MAXIMUM OPERATING TEMPERATURE OF THE OVEN WILL BE T = 250 C, WHILE THE AMBIENT TEMPERATURE IN THE KITCHEN IS T 25 "C. CALCULATE THE THICKNESS OF THE INSULATORS TO PREVENT THE OUTSIDE SURFACE OF THE OVEN FROM EXCEEDING 60 C. THE HEAT TRANSFER COEFFICIENTS ARE he 10 Kent /hr-m c BOTH OUTSIDE AND INSIDE THE KILN. THE THERMAL no CONDUCTIVITIES OF THE TWO INSULATORS ARE: