JEE Main & Advanced Physics Electrostatics & Capacitance Electric Flux

Electric flux is a measure of 'flow' of electric field through a surface. It is equal to the product of an area element and the perpendicular component of \[\overrightarrow{E}\], integrated over a surface.

(1) Flux of electric field \[\overrightarrow{E}\] through any area \[\overrightarrow{A}\] is defined as.

\[\varphi =E.A\cos \theta \]      or          \[\varphi =\overrightarrow{E}.\overrightarrow{A}\]

(2) In case of variable electric field or curved area.  \[\varphi =\int{\overrightarrow{E}.\,\overrightarrow{dA}}\]

(3) It's S.I. Unit is (Volt \[\times \] m) or \[\frac{N\text{-}{{m}^{2}}}{C}\]

(4) For a closed body outward flux is taken to be positive while inward flux is taken to be negative.