(a) Use Gauss's theorem to find the electric field due to a uniformly charged infinitely
Iarge plane thin sheet with surface charge density.` Sigma`
(b) An infinitely large thin plane sheet has a uniform surface charge density `+ sigma`. Obtain the
expression for the amount of work done in bringing a point charge q from infinity to a
point , distant r, in front of the charged plane sheet.

Explanation

(a) See Q . 20, Set- II , Delhi Borad-2009.
(b) ` E = (Sigma)/(2 in _(0)`
Amount of workdone =Potential `xx` Charge = `Vxxq`
`because (dV)/(dr) = E`
`rArr dV = Edr`
`therefore omega = Er xx q `
`omega = (sigma)/(2in_(0)) rq`
`omega = (sigmarq)/(2in_(0))`