Electric field outside of a cavity

[Domenico94]

Homework Statement

Hi everyone. I m just studying capacitors but I have problems with gauss law. In one exercise it says that we have a sphere(cavity) of radius r, with a charge q placed inside the sphere of it. Wie have to find the electric field inside and outside sphere.
The solution says: inside the sphere the electric field is q/4πeor^2,Outside of it the field is 0.
The thing I don't understand, why is the field 0?shouldn't we have a distribution of charge for which inside the sphere we have a charge -q, so the net field is 0,then on the surface we have a charge +q that gives an electric field,(q/4πr^2),similar to that of a point-like charge? Please help me

Homework Equations

The Attempt at a Solution

 

[haruspex]

Is this a cavity within a conductor, and you are asking about the field outside the cavity but still within the conductor? If not, please provide details exactly as stated in your referenced text.

 

[rude man]

I think you mean inside the cavity, and outside the cavity but still inside the sphere.