# physics

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An unclothed student is in a 27 degree Celsius room.
If the skin temperature of the student is 37 degree Celsius, how much heat is lost from his body in 18 minutes, assuming that the emissivity of the skin is 0.91 and the surface area of the student is 1.7 m^2. The Stephan-Boltzmann constant is 5.6696 x 10 ^-8 W/m^2 x K^4.

• physics -

change 18m to seconds (watts is a J/sec)

emissivity*Area*timeinseconds*stephanConstant*((273+37)^4-(273+27)^4)

I did a mental multipication and got about 100kJ
check that.

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