Characteristic resitance of rectangular waveguide for transverse magnetic waves
===============================================================================

The resistance of a rectangular waveguide to transverse magnetic waves can be calculated
from the resistance of the medium within the waveguide, the wavelength of the signal
and the critical wavelength of the waveguide.

**Conditions:**

#. Waves propagating in the waveguide must be transverse magnetic waves.

..
    TODO: find link

.. py:currentmodule:: symplyphysics.laws.electricity.circuits.waveguides.characteristic_resistance_of_rectangular_waveguide_for_transverse_magnetic_waves

.. py:data:: wave_impedance

    :attr:`~symplyphysics.symbols.electrodynamics.wave_impedance` in the waveguide.

Symbol:
    :code:`eta`

Latex:
    :math:`\eta`

Dimension:
    :code:`impedance`


.. py:data:: medium_impedance

    :attr:`~symplyphysics.symbols.electrodynamics.wave_impedance` of the medium filling the waveguide.

Symbol:
    :code:`eta_0`

Latex:
    :math:`\eta_{0}`

Dimension:
    :code:`impedance`


.. py:data:: vacuum_wavelength

    :attr:`~symplyphysics.symbols.classical_mechanics.wavelength` of the signal in vacuum.

Symbol:
    :code:`lambda`

Latex:
    :math:`\lambda`

Dimension:
    :code:`length`


.. py:data:: critical_wavelength

    Critical :attr:`~symplyphysics.symbols.classical_mechanics.wavelength`. See :ref:`Critical wavelength of waveguide <critical_wavelength_waveguide_def>`.

Symbol:
    :code:`lambda_c`

Latex:
    :math:`\lambda_\text{c}`

Dimension:
    :code:`length`


.. py:data:: law

    :code:`eta = eta_0 * sqrt(1 - (lambda / lambda_c)^2)`


    Latex:
        .. math::
            \eta = \eta_{0} \sqrt{1 - \left(\frac{\lambda}{\lambda_\text{c}}\right)^{2}}