Flux of Electric Current

In Electromagnetism, the electric field is defined as the measure of the flow of electric current through a given area. It is a property of an electric field that may be thought as electric field lines that intersect at a particular area. These field lines arise from +ve electric charges and cut off at -ve charges. Electric field lines that are conducted out of a sealed ( closed ) surface are +ve, and the lines that are carried out on a sealed surface are considered -ve.

Suppose if there is no net charge within a sealed surface than the field line that is conducted into the surface it continues to travel inwards of the surface and then it is led outwards somewhere on the surface. The net electric flux is ‘0’ when -ve flux is equal to +ve flux in magnitude. The unit of flux is Voltmeter.

  • Mathematically electric flux is defined as follows:
\(\Delta \Phi _{e}=\vec{E}.\Delta \vec{A}\)


\(\Delta\Phi _{e}=E;\Delta A\;Cos\Theta\)

Where theta represents angle between E and Delta A.

  • Zero Flux: No electric field lines will pass through a surface when it placed parallel to the electric field.
\(\Phi E=\vec{E}\;.\;Delta \vec{A}\) \(\Phi e=E\;\Delta A\;cos\;90^{\circ}\) \(\Phi e=E\;\Delta A\;(0)\) \(\Phi e=0\)
  • Maximum Flux: The maximum electric field lines of force passes through a surface when it is placed perpendicular to the electric field.
\(\Phi E=\vec{E}\;.\;Delta \vec{A}\) \(\Phi e=E\;\Delta A\;cos0^{\circ}\) \(\Phi e=E\;\Delta A\;(1)\) \(\Phi e=E\;Delta A\)

Gauss’s  Law

For an electric field, the mathematical relation between an enclosed charge and electric field is termed as Gauss’s Law. It is one among the core law in electromagnetism.

It simplifies the calculation for electric field for the geometry of sufficient symmetry. It is an important tool has it allows the appraisal of the volume of enclosed charges by mapping the field on a surface.

Practise This Question

etan1x(1+x+x2).d(cot1x) is equal to