In a Van de Graff type generator a spheri- - cal metal shell is to be a 15 x 10° V electrode. The dielectric strength of the gas surrounding the electrode is 5 x 107 Vm. What is the minimum radius of the spherical shell required ? (You will learn from this exercise why one cannot build and electrostatic generator using a very small shell which requires a small charge to acquire a high potential.)

In a Van de Graff type generator a spheri- - cal metal shell is to be a 15 x 10° V electrode. The dielectric strength of the gas surrounding the electrode is 5 x 107 Vm. What is the minimum radius of the spherical shell required ? (You will learn from this exercise why one cannot build and electrostatic generator using a very small shell which requires a small charge to acquire a high potential.)