Physics Question on Electric charges and fields

Question

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

Answer 1

Solution

The charge q, which is kept at the centre of metallic spherical shell transfered to the outer surface of shell and inside the shell the electric field is zero and hence force is also zero.