Question

For athermanous surface.........
a= ?​

Answer 1

Step-by-step explanation:

a = 1 ... at perfectly black body....

Answer 2

For athermanous surface a = 0.

• Athermanous substances:- When the transmission of the heat radiations occurs through the substances, then the substances which get heated by absorption of heat, are expressed as athermanous substances. Examples: glass, moist air, wood, water, and many more.
• Diathermanous substances:- When the transmission of the heat radiations occurs through the substances, which do not get heated by absorption of heat, such substances are expressed as diathermanous substances. Examples: rock salt, air, fluorspar, and many more.

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