Решение задачи по физике раздел 18 пункт 70 квантовая

70. Find the power P of electric current supplied to the tungsten filament diameter d = 0,5 mm and a length ℓ = 20 cm in order to maintain its temperature 3000 K is that the heat lost by radiation only. Ambient temperature 1000 K. The coefficient of thermal emission 0,3 tungsten.

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