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
Answer: Option D
Solution (By Examveda Team)
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 lawThis Question Belongs to Mechanical Engineering >> Heat And Mass Transfer
The heat is transferred by conduction, convection and radiation in
A. Melting of ice
B. Boiler furnaces
C. Condensation of steam in condenser
D. None of these
Heat is transferred by all three modes of transfer, viz. conduction, convection and radiation in
A. Electric heater
B. Steam condenser
C. Boiler
D. Refrigerator condenser coils
The radiation emitted by a black body is known as
A. Black radiation
B. Full radiation
C. Total radiation
D. All of these
Join The Discussion