Gibbs energy change via temperature change and electric displacement change
===========================================================================

The infinitesimal change in Gibbs energy of a system with a dielectric medium
can be expressed using the change in temperature and the change in electric
field strength.

**Conditions:**

#. The dielectric is isotropic whether or not the electric field is present.
#. The medium is homogeneous.
#. The volume change of the medium is insignificant.

**Links:**

#. Formula 31.8 on p. 122 of "General Course of Physics" (Obschiy kurs fiziki), vol. 3 by Sivukhin D.V. (1979).

.. py:currentmodule:: symplyphysics.laws.thermodynamics.dielectrics.gibbs_energy_change_via_temperature_change_and_electic_displacement_change

.. py:data:: gibbs_energy_density_change

    Infinitesimal change in :attr:`~symplyphysics.symbols.thermodynamics.gibbs_energy` of the system per unit :attr:`~symplyphysics.symbols.classical_mechanics.volume`.

Symbol:
    :code:`dG`

Latex:
    :math:`dG`

Dimension:
    :code:`energy/volume`


.. py:data:: entropy_density

    :attr:`~symplyphysics.symbols.thermodynamics.entropy` of the system per unit :attr:`~symplyphysics.symbols.classical_mechanics.volume`.

Symbol:
    :code:`S`

Latex:
    :math:`S`

Dimension:
    :code:`energy/(temperature*volume)`


.. py:data:: temperature_change

    Infinitesimal change in :attr:`~symplyphysics.symbols.thermodynamics.temperature` of the system.

Symbol:
    :code:`dT`

Latex:
    :math:`dT`

Dimension:
    :code:`temperature`


.. py:data:: electric_displacement

    :attr:`~symplyphysics.symbols.electrodynamics.electric_displacement`.

Symbol:
    :code:`D`

Latex:
    :math:`D`

Dimension:
    :code:`charge/area`


.. py:data:: electric_field_change

    Infinitesimal change in :attr:`~symplyphysics.symbols.electrodynamics.electric_field_strength`.

Symbol:
    :code:`dE`

Latex:
    :math:`dE`

Dimension:
    :code:`voltage/length`


.. py:data:: law

    :code:`dG = -S * dT - D * dE`


    Latex:
        .. math::
            dG = - S dT - D dE