Need help on this! Light bulb Filament Temperature with emissivity and δ given

1. Sep 21, 2006

sickid

Hi, I am stuck on this question, any help would be appreciated. Thanks!

1. The tungsten filament of a certain 100 W light bulb radiates 2.85 W of light. (The other 97.15 is carried away by convection and conduction) The filament has surface area of 0.400 mm^2 and an emissivity of 0.952. Find the filament's temperature in kelvin. (melting point of tungsten is 3683 K) Take δ 5.6696 X 10^-8 W/m^2.K^4

I tried to use the formula: P=eδAT^4 but I still can't get the right answer. I tried to do a search on internet, come across a lot of problem related to the above mentioned but the resistence and ohm is known. If you could point me to the right way, providing the right formula would be very much appreciated.

Last edited: Sep 21, 2006
2. Sep 22, 2006

andrevdh

What temperature did you get?