A point charge +???? is at the center of a spherical conducting shell of inner radius ????1 and outer radius ????2 as shown in the figure. Spherical shell with inner radius R subscript 1 and outer radius R subscript 2 encloses a point charge of charge plus Q located at its center. The total charge on the inner surface of the shell is +???? . ????? . 0 +????/2 . ?????/2 .