1. The earth receives about 430 W/m^2 from the sun, averaged over the whole surface, and radiates an equal amount back into space (that is , the earth is in equilibrium). Assuming the earth is a perfect emitter (e=1.0), estimate its averaged surface temperature.
2. A 100-W lightbulb generates a 95W of heat, which is dissipated through a galss bulb that has a radius of 3.0 and is 1.0mm thick. What is the difference in temperature between the inner and outer surface of the glass?
2007-05-09 18:54:17 · 2 answers · asked by petite fille 2 in Science & Mathematics ➔ Physics
hi!!! you can have a look through wikipedia's page. it will give you the right answer.
2007-05-09 19:30:08 · answer #1 · answered by Anonymous · 0⤊ 0⤋
1.
T^4 = (430 W/m^2)/(5.6704*10^-8 W/m^2°K^4)
T â 295.1°K â 22°C â 71.8°F
2.
[(95/(4Ï(0.029)^2)/(5.6704*10^-8 W/m^2°K^4)]^(1/4) â 631.0°K
[(95/(4Ï(0.03)^2)/(5.6704*10^-8 W/m^2°K^4)]^(1/4) â 620.4°K
âT â 10.6°C
2007-05-10 03:50:35 · answer #2 · answered by Helmut 7 · 0⤊ 0⤋