A conductor is an object or a type of substance that permits a charge to flow in one or more directions.
The conductor that permits the flow of charges through a central channel is referred to as a hollow conductor.
In comparison to solid conductors, hollow conductors have a larger diameter.
If a positive charge +Q is put in the middle of a hollow conductor, the charges are induced in this fashion that the inner faces are induced with a negative charge Q and become negative, while the outer faces are induced with a positive charge and become positive.
A Gaussian surface is a closed surface in three-dimensional space through which the flux of a vector field is calculated; usually the gravitational field, the electric field, or magnetic field.