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Heat Transfer - Engineering

Q1:

The ratio of total radiating power to the absorptivity of the body depends upon the __________ as per Kirchoffs law.

A wavelength of radiation

B nature of the body

C temperature of the body

D none of these

ANS:C - temperature of the body

According to Kirchhoff's law of thermal radiation, the ratio of the total radiating power of a body to its absorptivity depends only on the temperature of the body. This law states that at thermal equilibrium, the emissivity of a body (which is equal to its absorptivity at a given wavelength) is equal to its absorptivity. So, the correct answer is: "temperature of the body"