When a body is in thermal equilibrium with its surroundings, the absorptivity and the emissivity of the body are same. This Law is known as

Related MCQs

• In thermal radiation for a black body (where, ε is emissivity and α is absorptivity)
• The statement that the emissivity and absorptivity of a surface is surrounded by its own temperature are the same for both monochromatic and total radiation, is known as
• Absorptivity of a body will be equal to its emissivity
• The absorptivity of a body is equal to its emissivity
• Absorptivity of a perfect black body is unity. Which of the following has maximum absorptivity?
• The emissivity of a body will be equal to absorptivity when
• "The ratio of the total emissive power to the absorptivity for all bodies is same at ther-mal equilibrium". This is __________ law.
• Emissivity and absorptivity of a surface are equal for radiation
• A wall has two layers A and B, each made of a different material. Both the layers have the same thickness. The thermal conductivity of material of A is twice that of B. Under the thermal equilibrium the temperature difference across the wall is 30?C. The temperature drops in layers A and B will be respectively
• A 10 cm dia steam pipe, carrying steam at 180°C, is covered with an insulation (conductivity = 0.6 W/m.°C). It losses heat to the surroundings at 30°C. Assume a heat transfer co-efficient of 0.8 W/m2 .°C for heat transfer from surface to the surroundings. Neglect wall resistance of the pipe and film resistance of steam. If the insulation thickness is 2 cms, the rate of heat loss from this insulated pipe will be