A single charge in vacuum has imaginary equipotential surfaces around it which arc spherical, due to the symmetry. Assume we have a charge q = 4 x 10-10 C and such a surface with potential V= 36V.
Part (a) Input an expression for the radius of this surface, r.
Part (b) What is the radius in m?
Part (c) At what distance can a 10,000 V equipotential surface be found, r2?