This Demonstration shows the electric field, voltage and capacitance for an ideal concentric sphere capacitor. The inner sphere is held constant at ground or zero voltage while the voltage of the outer sphere is varied. The electric field between the capacitor plates is represented by arrows. It is nonzero only between the two spheres. Since we consider only what is happening between the two spheres, not outside or within the smaller sphere, the plot range of the graph is scaled to show the range of interest. Radii are expressed in meters (m), voltage in volts (V).