1. The problem statement, all variables and given/known data I have a sentence in my textbook that reads: Because the "breakdown" electric field in air is about 3 X 106 V/m, a sphere 1.00m in radius can be raised to a maximum potential of 3 X 106 V And now the problem states: The metallic sphere on top of a large van de Graaf generator has a radius of 2.0 m. Suppose that the sphere carries a charge of 3x10-5 C 2. Relevant equations V = Q/4∏rε0 3. The attempt at a solution Does that mean to find the Volt, I have to simply multiply that 3 X 106 V by 2, to give me 6 X 106 V? Or do I have to use the above equation to find the volt inside the generator?