boltzmann's constant
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Definition
- Noun:
- A fundamental physical constant: Boltzmann's constant is a physical constant that relates the average kinetic energy of particles in a gas with the temperature of the gas. It is a key parameter in statistical mechanics and thermodynamics.
Usage Examples
- Noun:
- The value of Boltzmann's constant is approximately 1.380649 × 10⁻²³ joules per kelvin.
- In the formula for entropy, Boltzmann's constant appears as a scaling factor.
Advanced Usage
In the Boltzmann entropy formula: Boltzmann's constant is central to the definition of entropy in statistical mechanics, expressed as S = kB ln Ω, where kB is Boltzmann's constant and Ω is the number of microstates.
- The profound equation S = k_B ln Ω is engraved on Ludwig Boltzmann's tombstone.
In the ideal gas law: Boltzmann's constant provides the microscopic connection in the kinetic theory of gases, linking pressure and volume to temperature.
- The product of the Boltzmann constant and Avogadro's number yields the ideal gas constant.
Variants and Related Words
Boltzmann factor (n): A weighting factor that determines the relative probability of a system being in a certain state, given by exp(-E/(kB T)), where kB is Boltzmann's constant.
- The Boltzmann factor is crucial for calculating population distributions in thermal equilibrium.
Stefan-Boltzmann constant (n): A derived constant in the law for thermal radiation, related to but distinct from Boltzmann's constant.
- The Stefan-Boltzmann constant is denoted by σ and is derived using Boltzmann's constant.
Synonyms
- k_B: The standard symbol for Boltzmann's constant.
- Boltzmann constant: An alternative naming with the same meaning.
Related Phrases
- Boltzmann's constant times temperature: Often appears as the thermal energy scale, k
- At room temperature, kB T is about 4.11 × 10⁻²¹ joules.
Related Concepts
- Ideal gas constant: The molar gas constant R, which is equal to Boltzmann's constant multiplied by Avogadro's number (R = kA).
- Thermodynamic beta: Defined as β = 1/(k_B T), a parameter frequently used in statistical mechanics.
Noun
- constant used in the calculation of the ideal gas constant