Question

A disc having a uniform charge density σ and radius R is placed on x−y plane with centre at the origin . Find the electric potential at a point on z - axis at a distance 10m from centre . σ=16∈0,R=1m

Answer 1

(b) 0.4

Explanation : potential due to whole disc = σ2∈0[R2+x2−−−−−−√−x]

Since x > > R

V=σ2∈0[x(1+R2x2)12−x]

V=σ2∈0[x+R22x−x]

V=σR24∈0x

V=(16∈0)14∈010=0.4.