Figure shows a conducting sphere with a cavity. A point charge q₁, is placed inside cavity, and q₂ is placed out side the sphere. ${\overrightarrow{\mathrm{E}}}_{\mathrm{in}}$ is electric field due to charge induced on surface of cavity. ${\overrightarrow{\mathrm{E}}}_{\mathrm{out}}$ is electric field due to charge induced on outer surface of sphere and ${\overrightarrow{\mathrm{E}}}_{\text{net }}$ is net field at any point. Two closed gaussian surface S₁ & S₂ are also drawn in the figure.