why is electrostatic potential constant throughout the volume of the conductor and has the same value(as inside) on its surface??
as electric field inside the conductor is zero so there is no work done in moving a small test charge within the conductor.therefore there is no potential difference between any two points inside the conductor that is electrostatic potential is constant throughout the volume of the conductor.
Where E is the electric field and v is the potential and r is the distance.
Since inside a conductor the E field is zero.
=>dV=0 i.e the change in potential inside the conductor is a constant.
And this value is k Q/r where k is the constant and Q is the Charge on the surface of the conductor.
And r is the radius.