In: Physics
Use Gauss's law to prove that the electric field outside any spherically symmetric charge distribution is the same as if all of the charge were concentrated into a point charge at the center of the sphere. Then use Gauss's law to prove that the electric field inside a spherically symmetric conductor carrying a net charge on its surface is zero.

Consider a charge distribution having charge 'Q" uniformly distrubuted
Consider a gassian surface of radius 'r' outside the charge distribution .
According to gauss's law
E. A = qenclosed /
o
enclosed charge inside the gaussian surface = Q
Area of gaussian surface = A = 4
r2
E (4
r2) = Q/
o
E = Q/ (4
o
r2)
Consider a gassian surface of radius 'R' inside the charge distribution .
According to gauss's law
E. A = qenclosed /
o
enclosed charge inside the gaussian surface = 0, (since there is no charge inside)
Area of gaussian surface = A = 4
r2
E (4
r2) = 0/
o
E = 0