IIT JEE , AIEEE Forum - Physics , Electricity - Non conducting sphere and sherical shell problem.

angad7

A non conducting solid sphere of radius 'a' with a charge +Q unformly ditributed throughout its volume is concetric with a non conducting spherical shell of inner radius '2a' and outer radius 3a that has a charge -Q uniformly ditributed troughout its volume.

<a> using gauss law, derive expressions for the magnitude of the e.field as a function of radius r in the following regions

1) within the solid sphere ( r<a)

2) b/w the solid sphere and spherical shell ( a<r<2a)

3) within the spherical shell 2a<r<3a

4) outside the pherical shell r> 3a

pls solve the problem...with every step.

pink_ele

within the sphere charge is zero so ...........
field is zero
b/w
hrcharge is q so atdistance r field is
using guass law
E x 4 pi r^2=Q/e not
or
E=Q/4pi r^2e not

c)outside d shell
again total charge is zero
so field is zero

pink_ele

now for part c )
at a dis tance of 2a +r
net charge=Q-Q/(vol of shell))x(vol of shell formed within req distance)
=Q-(Q/19a^3) x(r^3-8a^3)
=Q(11a^3-r^3)
therefore
Ex 4 pi (2a+r)^2=Q(11a^3-r^3)/e not
E=Q(11a^3-r^3)/4 pi (2a+r)^2 e not

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