Question
What is electric flux? Write its S.I. units.
Using Gauss’s theorem, deduce an expression for the electric field at a point due to a uniformly charged infinite plane sheet.
✓
Answer
Electric Flux: Total number of electric lines of force crossing a certain area normally.
Alternate Answer
The surface integral of electric field over a closed surface.
Alternate Answer
$\phi = \oint\overrightarrow{\text{E}}.\text{d}\overrightarrow{\text{s}}$
- S.I. Units: Nm2 /C Or V-m
Derivation: $\phi= \oint_{s}\overrightarrow{\text{E}}.\overrightarrow{\text{ds}}= \frac{\text{q}}{\varepsilon_\circ}$
$2\text{EA} =\frac{\sigma\text{A}}{\varepsilon_\circ}$
$\therefore \text{E} =\frac{\sigma}{2\varepsilon_{\circ}}$
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