A metallic sphere having radius 0.08m and mass m = 10 kg is heated to a temperature of 227∘ Cand suspended inside a box whose walls are at a temperature of 27∘ C. The maximum rate at which its temperature will fall is Take e=1, σ=5.8×10−8 Wm−2 K−4 and specific heat of the metal S=90 cal/kg/k; J=4.2 J/cal)
0.066∘ C/s
P=eσA(ΔT)4=msdTdt⇒dTdt=eσA(ΔT)4ms