1 The Rate Of Heat Conduction Out Of A Window On A Winter Day Is Rapid Enough To Chill The Air Next To It To See Just 1 (83.15 KiB) Viewed 12 times
1. The rate of heat conduction out of a window on a winter day is rapid enough to chill the air next to it. To see just how rapidly the windows transfer heat by conduction, calculate the rate of conduction in watts through a 2.5 m² window that is 0.635 cm thick (1/4 in) if the temperatures of the inner and outer surfaces are 6 °C and -11 °C, respectively. This rapid rate will not be maintained—the inner surface will cool, and even result in frost formation. The coefficient of heat conduction for glass k=0.84 J/(s m °C). Q/t= vw
a 1. At what net rate does heat radiate from a 175- m? black roof on a night when the roof's temperature is 30°C and the surrounding temperature is 15°C? The emissivity of the roof is 0.900. The Stefan-Boltzmann's constant is o=5.67 x 10-8 J/(s m2 K4). Hint: The roof radiates heat to the surroundings but also absorbs heat from the surroundings. Use the sign convention for heat leaving and entering a system. Pn Pnet = Q/t= 13834.6 XV w =
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