Figure shows two concentric spheres of radii `R_(1)` and `R_(2) (R_(2) gt R_(1))` which contain uniformly distributed charges Q and -Q respectively. Find out electric field intensities at the following positions :

(i) `r lt R_(1)` (ii) `R_(1) le r le R_(2)` (iii) `r ge R_(2)`

Explanation

Net electric field `=E_(1)+E_(2)`
`E_(1)=` field due to sphere of radius `R_(1)`
`E_(2)=` field due of sphere of radius `R_(2)`
(i) `E_(1)=0, E_(2)=0" ":. E_("net")=0`
(ii) `E_(1)=(KQ)/r^(2), E_(2)=0" "implies vec(E)=(Kq)/r^(2) hat(r)`
(iii) `vec(E)_(1) =(kq)/r^(2) hat(r) vec(E)_(2)=(Kq)/r^(2) (-hat(r))" "implies vec(E)_("net")=vec(E)_(1)+vec(E)_(2)=0`