Capacitance For Earth As A Spherical Capacitor Model The Earth As An Air-Filled Spherical Capacitor With The Negative Plate At The Surface Of The Earth And The Positive Plate At The Bottom Of The Ionosphere, At An Altitude Of ∼70 Km. The Potential Difference Between Earth's Surface And Ionosphere Is ∼350,000 V. A) What Are The Values Of R1 And R2 ? B)