Capacity of an Isolated Spherical Conductor

Let a charge q be given to the sphere which is assumed to be concentrated at the centre. Potential at any point on the surface is

1. Capacitance of a spherical conductor is directly proportional to its radius.
2. The above equation is true for conducting spheres, hollow or solid.
3. If the sphere is in a medium, then C = 4πε0εr.R
4. Capacitance of the earth is 711 μF.