The black body which is most close to a perfect body is:
Correct answer: B. Cavity Radiator
- A. Translucent glass box
- B. Cavity Radiator
- C. Black holes
- D. All of these options are correct
Explanation
A perfect black body at a constant temperature absorbs and re-emits all the electromagnetic radiation that falls on it. OPTION A: If a material is translucent, some light can pass through it. OPTION B: A cavity radiator is a hollow sphere with a small hole through which radiation can enter and leave. Radiation that enters the hole is reflected continuously within the sphere until it is completely absorbed (as would be the case with a blackbody). Hence, B is the correct option. OPTION C: A black hole is a region of space having a gravitational field so intense that no matter or radiation can escape.OPTION D: It is an incorrect option.
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Classical physics cannot explain blackbody radiation and related observations, leading to Planck’s quantum theory, in which energy is emitted or absorbed in discrete packets. Photons provide the particle model of light, with energy and momentum linked to frequency and wavelength, including the photoelectric effect and its threshold frequency.
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