It may be noted that the electric field strength is independent of distance. This is true for the infinite plane of charge; electric lines of force on either side of the charge will be perpendicular to the sheet and extend to infinity as parallel lines. As number of lines of force per unit area gives the strength of the field, the field becomes independent of distance. For a finite charge sheet, the field will be a function of distance.
3. Uniformly Charged Sphere
Let us consider a sphere of radius r0 having a uniform volume charge density of rv C/m3. To determine 
everywhere, inside and outside the sphere, we construct Gaussian surfaces of radius r < r0 and r > r0 as shown in Fig. 2.6 (a) and Fig. 2.6(b).
For the region 
; the total enclosed charge will be
.........................(2.18)
Fig 2.6: Uniformly Charged Sphere