Q71
According of Kirchhoff's law
A.
Radiant heat is proportional to fourth power of absolute temperature
B.
Emissive power depends on temperature
C.
Emissive power and absorptivity are constant for all bodies
D.
Ratio of emissive power to absorptive power for all bodies is same and is equal to the emissive power of a perfectly black body
AnswerAnswer: Option D
Solution
Answer: Option D
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