# What is Boltzmann Constant?

Level 2 (without higher mathematics)

The Boltzmann constant is a physical constant and is denoted by $$k_{\text B}$$. It has the following exact value:

Value of the Boltzmann constant
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• The unit of the Boltzmann constant is Joule per Kelvin:

Unit of the Boltzmann constant
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• The value 1 of the Boltzmann constant can also be expressed in electron-volts (eV) per kelvin. To do this, we need to convert 1 joule to electron-volts. This results in the following value of $$k_{\text B}$$ in electron-volts per kelvin:

Boltzmann constant in electron volts per kelvin
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• The Boltzmann constant occurs in the equations that describe systems with many particles. So you will often encounter the Boltzmann constant in statistical physics and solid state physics.

• The Boltzmann constant links the molar gas constant $$R_{\text m}$$ with the Avogardo constant $$N_{\text A}$$:

Molar gas constant via Boltzmann constant
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• The Boltzmann constant links energy to temperature in our universe.

• The Boltzmann constant can be determined, for example, by measuring the speed of sound in a gas. 