Difficulty: Easy
Correct Answer: False
Explanation:
Introduction / Context:Blackbody radiation is a cornerstone concept in heat transfer and thermodynamics. It defines ideal absorption and emission characteristics and underpins Planck’s law and Stefan–Boltzmann law.
Given Data / Assumptions:
Concept / Approach:A black body absorbs all incident radiation (it does not reflect or transmit). It also is the most efficient emitter at a given temperature. Therefore, the statement that it “rejects” all radiation is the opposite of the definition.
Step-by-Step Solution:
Define black body: absorptivity = 1, reflectivity = 0, transmissivity = 0.Kirchhoff’s law connects high absorptivity to high emissive power at the same temperature.Conclude that a black body does not reject radiation; it absorbs all and emits maximally.Hence, the statement is false.Verification / Alternative check:Compare to “white body,” which reflects; black body exhibits the opposite behaviour.
Why Other Options Are Wrong:Conditional “true” options conflict with the universal definition; wavelength or medium does not reverse the black body’s absorbing nature.
Common Pitfalls:Confusing “black” with non-emitting; in thermal radiation, a perfect absorber is also a perfect emitter at that temperature.
Final Answer:False
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