A conducting shell of radius R carries charge `-Q`. A point charge `+Q` is placed at the centre. The electric field E varies with distance `r` (from the centre of the shell) as

A conducting shell of radius R carries charge–Q. A point charge +Q is placed at the centre of shell. The electric field E varies with distance r (from the centre of the shell) as :

A thin spherical conducting shell of radius R has a charge q. Another charge Q is placed at the centre of the shell. The electrostatic potential at a point P a distance R/2 from the centre of the shell is

A thin spherical conducting shell of radius R has a charge q. Another charge Q is placed at the centre of the shell. The electrostatic potential at a point P a distance R/2 from the centre of the shell is

A thin spherical conducting shell of radius R has a charge q. Another charge Q is placed at the centre of the shell. The electrostatic potential at a point P a distance R/2 from the centre of the shell is

A thin spherical conducting shell of radius R has a charge q. Another charge Q is placed at the centre of the shell. The electrostatic potential at a point P a distance R/2 from the centre of the shell is

A thin metallic spherical shell of radius R carries a charge Q on its surface. A point charge Q/2 is placed at its centre C and another charge +2Q outside the shell at a distance r from the centre as shown in figure. Find the force on the charge at the centre of shell and at point A.