Demonstrate that at a dielectric-conductor interface the surface density of the dielectric's bound charge σ′=−σ(ε−1)/ε,\sigma^{\prime}=-\sigma(\varepsilon-1) / \varepsilon,σ′=−σ(ε−1)/ε, where ε\varepsilonε is the permittivity, σ\sigmaσ is the surface density of the charge on the conductor. . .