Problem 3.101

Find the capacitance of an isolated ball-shaped conductor of radius $R_{1}$ surrounded by an adjacent concentric layer of dielectric with permittivity $\varepsilon$ and outside radius $R_{2}$ .

C=\frac{4 \pi \varepsilon_{0} \varepsilon R_{1}}{1+(\varepsilon-1) R_{1} / R_{2}}

Electric Capacitance, Energy of an Electric Field