All Problems

Electric Capacitance, Energy of an Electric Field

Problem 3.110

Find the capacitance of a system of two identical metal balls of radius \(a\) if the distance between their centres is equal to \(b\). with \(b \gg a\). The system is located in a uniform dielectric with permittivity \(\varepsilon\).

Reveal Answer
C2πε0εa. Instruction. When ba, the charges can be assumed to be distributed practically uniformly over the surfaces of the balls. C \approx 2 \pi \varepsilon_{0} \varepsilon a . \text { Instruction. When } b \gg a, \text { the charges can be assumed to be distributed practically uniformly over the surfaces of the balls. }