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Heat and Mass Transfer
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The total emissivity power is defined as the total amount of radiation emitted by a black body per unit

Answer & Solution
Correct Answer: Option C
Total emissive power refers to the total amount of thermal radiation emitted by a surface (typically a black body) across all wavelengths per unit time and per unit area.

This concept is governed by Stefan-Boltzmann law, which states:

E = σT⁴

Where:
E = Total emissive power
σ = Stefan-Boltzmann constant
T = Absolute temperature of the black body

As per the definition, the total emissive power is expressed in units of watts per square meter (W/m²), indicating that it is radiation emitted per unit area.

Therefore, the correct answer is: Area (Option C).
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5 Comments
Ayaz Ali
Ayaz Ali 1 year ago
The total amount of thermal radiation emitted by a surface per unit area per unit time
Correct ans is unit Area
Kashif Alim
Kashif Alim 5 years ago
Area and time both
Deep Pakawala
Deep Pakawala 6 years ago
Area and time both
Odisha Free
Odisha Free 6 years ago
Time
Sarveshwer Chandra
Sarveshwer Chandra 6 years ago
Time