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Electric Charges and Fields — Physics STD 12 Science — Question

Gujarat BoardEnglish MediumSTD 12 SciencePhysicsElectric Charges and Fields2 Marks
Question
A thin straight infinitely long conducting wire having charge density λ is enclosed by a cylindrical surface of radius r and length l, its axis coinciding with the length of the wire. Find the expression for the electric flux through the surface of the cylinder.
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Answer

Charge enclosed by the cylindrical surface $\text{q} = \lambda l $ Flux $\varphi =\frac{\text{q}}{\varepsilon_{0}}$$ = \frac{\lambda l }{\varepsilon_{0}}$
Alternate Answer
$\varphi = \oint\overrightarrow{\text{E}}.\text{d}\overrightarrow{\text{S}} = \frac{\text{q}}{\varepsilon_{0}}$
$\varphi = \frac{\lambda l }{\varepsilon_{0}}.$

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