Question:
The absorption coefficient value of a perfect black body is
The absorption coefficient value of a perfect black body is
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A perfect black body is also an ideal emitter. According to Kirchhoff's law of thermal radiation, for an object in thermal equilibrium, the emissivity and the absorptivity are equal.
Updated On: Mar 22, 2025
- zero
- \(<1 \)
- \(>1 \)
- \( 1 \)
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The Correct Option is D
Solution and Explanation
The absorption coefficient \( \alpha \) of a material is a measure of how much radiation it absorbs compared to how much it reflects or transmits. A perfect black body is an idealized physical body that absorbs all incident electromagnetic radiation, regardless of frequency or angle of incidence. Thus, the absorption coefficient of a perfect black body is:
\[
\alpha = 1
\]
This means it absorbs all incident radiation and does not reflect or transmit any, making it a perfect absorber.
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