A solid conducting sphere of radius R is surrounded by a concentric metallic shell of inner radius 2R and outer radius 3R. The shell is earthed. The inner sphere is connected to a switch S by a thin conducting wire through a small hole in the shell. By closing the switch S, the inner sphere is connected to a distant conducting sphere of radius R having charge Q. Find the charge that flows to earth through wire AB.

Answer

`(2Q)/(3)`