76. The diameter of the tungsten filament in the light bulb d = 0,3 mm, l = length of the spiral 5 cm. When the lights in the network voltage U = 127 V current flows through the bulb I = 0,31 A. Find the temperature T coil. Believes that a balance all the earmarks in the yarn heat is lost by radiation. The ratio of tungsten and irradiance of a blackbody at a given temperature k = 0,31.

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