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Mechanical Engineering · Q64

Heat And Mass Transfer

Engineering and GATE · Mechanical Engineering · question 64

Q64

The ratio of the emissive power and absorptive power of all bodies is the same and is equal to the emissive power of a perfectly black body. This statement is known as

A.
Wien's law
B.
Stefan's law
C.
Kirchhoff's law
Answer
D.
Planck's law

Answer: Option C

Solution

Answer: Option C
Solution:
Kirchhoff's law states that the emissivity and the absorptivity of a surface at a given temperature and wavelength are equal.
The ratio of the emissive power and absorptive power of all bodies is the same and is equal to the emissive power of a perfectly black body. This statement is known as Kirchhoff's law