Question

Actually I asked this question in chat but no one replied. Can anyone explain me why the electric field due to a solid charged sphere and a hollow sphere same (for all cases)?

Answer 1

if both the solid and hollow sphere have the same charge, electric field due to them will be the same.
in both the cases the total charge is assumed to be at the center of the sphere and then the electric filed is found.

Answer 2

if we take a gaussian surface around both of them we can easily prove that the electric field at a point outside of the sphere is same due to both, but if a point is inside the sphere. The electric field due to hollow sphere at the point will be zero but for a solid sphere it'll have a value