Black Body Radiation: Classical Equipartition vs Boltzmann Distribution

In summary, the conversation discusses the discrepancy between the classical equipartition theorem and the Boltzmann distribution in explaining the energy distribution in the standard cavity experiment for black body radiation. This contradiction was eventually resolved by the introduction of Planck's distribution, which confirmed the principles of quantum theory.
  • #1
tut_einstein
31
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If you consider the standard cavity experiment for black body radiation, you know that the number of standing wave modes at higher frequencies is higher than the number of modes at lower frequencies. Therefore, according to classical equipartition theorem, there should be more energy in the higher frequencies. However, the Boltzmann distribution, which also holds classically predicts that there's a greater probability of finding the system in a lower energy state. Why do the two contradict or am I missing something here?

Thanks!
 
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  • #2
You meant Planck's distribution, not Boltzmann's?
It can't be explained in classical physics. Actually, the explanation of black body radiation distribution was one of the milestones confirming quantum theory 100 years ago.
 

1. What is black body radiation?

Black body radiation is the electromagnetic radiation emitted by a perfect absorber and emitter of energy, also known as a black body. It is a theoretical concept used to study the behavior of thermal radiation.

2. What is the difference between classical equipartition and Boltzmann distribution?

Classical equipartition is a theory that states that energy is equally distributed among all degrees of freedom in a system, while Boltzmann distribution is a statistical distribution that describes the probability of a particle occupying a certain energy state in a system.

3. How does black body radiation relate to classical equipartition and Boltzmann distribution?

Black body radiation follows the principles of classical equipartition and Boltzmann distribution. The energy of black body radiation is distributed among all possible modes of vibration, each of which is described by a different energy state according to Boltzmann distribution.

4. What is the significance of black body radiation in physics?

Black body radiation is important in understanding the behavior of thermal radiation and has been used to develop the concepts of quantum mechanics and the theory of relativity. It also has practical implications in fields such as astrophysics and materials science.

5. How is black body radiation experimentally studied?

Black body radiation can be studied through experiments using devices called black body radiators, which are objects that absorb and emit all radiation that falls on them. These experiments involve measuring the wavelength and intensity of the radiation emitted at different temperatures, which can then be compared to theoretical predictions based on classical equipartition and Boltzmann distribution.

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