So for my physics independent study project. I am studying the resistance vs. temperature in non-ohmic material. I passed different currents through the light bulb and took the surface temperature with a thermocouple. How can I find the temperature of filament using the surface temperature measurement? My teacher seemed to think that would be easy, but I can't find it anywhere. Can anyone please help me? I do not want to start my project all over again and I don't know how I would even measure the temperature of the filament seeing as my school does not own a optical pyrometer. Thanks.