A light bulb filament is constructed from 2 cm of tungsten wire of diameter 50 m and

Question:

A light bulb filament is constructed from 2 cm of tungsten wire of diameter 50 μm and is enclosed in an evacuated glass bulb. What temperature does the filament reach when it is operated at a power of 1 W? (Assume the emissivity of the tungsten surface to be 0.4.)