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If you calculate the thermal power radiated by typical objects at room temperature, you will find surprisingly large values, several kilowatts typically. for example, a square box that is 1 m on each side and painted black (therefore justifying an emissivity e near unity) emits 2.5 kw at a temperature of 20∘c. in reality the net thermal power emitted by such a box must be much smaller than this, or else the box would cool off quite quickly. which of the following alternatives seems to explain this conundrum best? a. the box is black only in the visible spectrum; in the infrared (where it radiates) it is quite shiny and radiates little power.
b. the surrounding room is near the temperature of the box and radiates about 2.5 kw of thermal energy into the box.
c. both of the first two factors contribute significantly.
d. neither of the first two factors is the explanation.
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