42. The iron ball of 10 cm diameter, heated to a temperature of 1227° C, cools outdoors. After some time, the temperature will drop to 1000 K? In the calculation we assume that the ball radiates as gray body with an absorption coefficient (absorption capacity) 0.5. Thermal conductivity of air is not considered.

Detailed solution. Decorated in Microsoft Word 2003. (Target decided to use formula editor)