A spherical conductor is charged up to a potential of $$450\,\text{V}$$. The potential outside, at a distance $$15\,\text{cm}$$ from the surface, is $$300\,\text{V}$$. Then

A

the potential at $$15\,\text{cm}$$ from the center is $$900\,\text{V}$$

B

the charge on the conductor is $$1.5\,\text{nC}$$

C

the electric field just outside the surface is $$150\,\text{N C}^{-1}$$

D

the total electrical energy of the conductor is $$U=3.375\,\mu\text{J}$$