Wave speed from medium permittivity and permeability
====================================================

Speed of electromagnetic wave propagation depends on relative permittivity and relative
permeability of the medium.

**Notation:**

#. :math:`c` (:code:`c`) is :attr:`~symplyphysics.quantities.speed_of_light`.

**Links:**

#. `Wikipedia, derivable from here <https://en.wikipedia.org/wiki/Phase_velocity#Refractive_index>`__.

.. py:currentmodule:: symplyphysics.laws.waves.wavespeed_from_medium_permittivity_and_permeability

.. py:data:: wave_speed

    Speed of wave propagation in medium. See :attr:`~symplyphysics.symbols.classical_mechanics.phase_speed`.

Symbol:
    :code:`v`

Latex:
    :math:`v`

Dimension:
    :code:`velocity`


.. py:data:: relative_permittivity

    :attr:`~symplyphysics.symbols.electrodynamics.relative_permittivity` of the medium.

Symbol:
    :code:`epsilon_r`

Latex:
    :math:`\varepsilon_\text{r}`

Dimension:
    :code:`dimensionless`


.. py:data:: relative_permeability

    :attr:`~symplyphysics.symbols.electrodynamics.relative_permeability` of the medium.

Symbol:
    :code:`mu_r`

Latex:
    :math:`\mu_\text{r}`

Dimension:
    :code:`dimensionless`


.. py:data:: law

    :code:`v = c / sqrt(epsilon_r * mu_r)`


    Latex:
        .. math::
            v = \frac{c}{\sqrt{\varepsilon_\text{r} \mu_\text{r}}}