Photon momentum is proportional to energy
=========================================

The momentum of a photon is its energy divided by the speed of light.

See :ref:`Photon energy is proportional to angular frequency` or
:ref:`Photon energy is proportional to linear frequency` for energy
expressions.

**Notation:**

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

**Conditions:**

#. Works in a **vacuum** environment.

**Links:**

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

.. py:currentmodule:: symplyphysics.quantum_physics.photons.photon_momentum_is_proportional_to_energy

.. py:data:: momentum

    :attr:`~symplyphysics.symbols.classical_mechanics.momentum` of a photon.

Symbol:
    :code:`p`

Latex:
    :math:`p`

Dimension:
    :code:`momentum`


.. py:data:: energy

    :attr:`~symplyphysics.symbols.basic.energy` of a photon.

Symbol:
    :code:`E`

Latex:
    :math:`E`

Dimension:
    :code:`energy`


.. py:data:: law

    :code:`p = E / c`


    Latex:
        .. math::
            p = \frac{E}{c}