The dome of a Van de Graaff generator has a diameter of 32.0 cm and is surrounded by dry air with a 'breakdown' electric field of 3.00 106 V/m.

Question

The dome of a Van de Graaff generator has a diameter of 32.0 cm and is surrounded by dry air with a 'breakdown' electric field of 3.00  106 V/m. 
What is the maximum potential of the dome?