A point charge q is placed in a cavity in a metal block. If a charge Q is brought outside the metal, will the charge q feel an electric force?

A thin metallic spherical shell contains a charge Q on it. A point charge q is placed at the centre of the shell and another charge q_(1) is placed outside it as shown in figure. All the three charges are positive The force on the charge at the centre is

A thin metallic spherical shell contains a charge Q on it. A point charge q is placed at the center of the shell and another charge q_1 is placed outside it as shown in the figure. All the three charges are positive. Find the force on the charge a. at centre due to all charges. b. at center due to shell.

A spherical metallic conductor has a spherical cavity. A positive charge is placed inside the cavity at its centre. Another positive charge is placed outside it. The conductor is initially electrically neutral. {:(,"Column I (Cause)",,,"Column II (Effect)"),((A),"If outside is shifted to other position",,(p),"Distribution of charge on innner surface"),(,,,,"of cavity charges"),((B),"If inside charge is shifted to other position",,(q),"Distribution of charge on outer surface of"),(,,,,"conductor charges"),((C),"If magnitude of charge inside cavity is",,(r),"Electric potential at the centre of conductor"),(,"increased",,,"changes due to charges present"),(,,,,"on outer surface of conductor"),((D),"If conductor is earthed",,(s),"Force on the charge placed inside"),(,,,,"cavity changes"):}

A charge Q is enclosed by a spherical Gaussian surface of radius R. If the radius of the sphere is double, how will the outward electric flux charge ? If a charge -Q is brought outside the Gaussian surface, will the electric flux reduce to zero ?