Mean free path of random motion
===============================

The mean free path of a molecule in random motion is its average path length between collisions.

**Conditions:**

#. Spherical model of molecules is assumed.

**Links:**

#. `Wikipedia <https://en.wikipedia.org/wiki/Mean_free_path#Kinetic_theory_of_gases>`__.

..
    NOTE: replace `pi * d^2` with cross-section?

.. py:currentmodule:: symplyphysics.laws.thermodynamics.mean_free_path_of_random_motion

.. py:data:: mean_free_path

    :attr:`~symplyphysics.symbols.thermodynamics.mean_free_path` estimate of molecules.

Symbol:
    :code:`lambda`

Latex:
    :math:`\lambda`

Dimension:
    :code:`length`


.. py:data:: molecular_diameter

    :attr:`~symplyphysics.symbols.classical_mechanics.diameter` of molecules.

Symbol:
    :code:`D`

Latex:
    :math:`D`

Dimension:
    :code:`length`


.. py:data:: number_density

    :attr:`~symplyphysics.symbols.basic.number_density` of the system.

Symbol:
    :code:`n`

Latex:
    :math:`n`

Dimension:
    :code:`1/volume`


.. py:data:: law

    :code:`lambda = 1 / (sqrt(2) * pi * D^2 * n)`


    Latex:
        .. math::
            \lambda = \frac{1}{\sqrt{2} \pi D^{2} n}