Math CentralQuandaries & Queries


Question from florence, a student:


I have a college tutor and we are stumped with this question.

Assuming a filament in a 100 W light bulb acts like a perfect blackbody, what is the temperature of the hottest portion of the filament if it has a surface area of 6.3 X 10-5 m2? The Stefan-Boltzmann constant is 5.67 X 10-4 W/(m2 X K2.\

Thank you for your help. If you can only answer one question per day please answer this one and guide me through a solution.

Hi Florence,

You need the Stefan-Boltzmann Law to solve the question:

Where P is the power and T is the absolute temperature.

Hope this helps,



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