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A food industry keeps food cool in a very crude...

A food industry keeps food cool in a very crude manner, by radiation. It paints its walls white and not black, because of _____

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+1 vote

asked Jan 30, 2022 in Food Engineering by Amelia (93.8k points)

A food industry keeps food cool in a very crude manner, by radiation. It paints its walls white and not black, because of _____

(a) Kirchhoff’s Law

(b) Stephan-Boltzmann Law

(c) None of the mentioned

(d) Kirchhoff’s Law & Stephan-Boltzmann Law

I have been asked this question during a job interview.

This interesting question is from Unit Operations topic in division Heat Transfer by Conduction, Convection and Radiation of Food Engineering

food engineering
heat transfer by conduction
convection and radiation
unit operations

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1 Answer

+2 votes

answered Jan 30, 2022 by Mason (380k points)
selected Feb 3, 2022 by Amelia

Best answer

Right choice is (a) Kirchhoff’s Law

To explain I would say: Kirchhoff’s law states that at temperature equilibrium, the absorptivity of a grey body is equal to its emissivity. Since white paint has less emissivity than that of black paint, the wall is painted white.

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