The equipotential surfaces surrounding a point charge are concentric spheres with the charge at the center. If the electric pote
ntial of two such equipotential surfaces that surround a point charge 1.63 10-8 C are 200 V and 82.0 V, what is the distance between these two surfaces?
Since the charge is at the centre of two concentric spheres, we use the formula for electric potential due to a point charge. V = kq/r. Let r₁ be the radius of the sphere with potential, V₁ = 200 V and r₂ be the radius of the sphere with potential, V₂ = 82.0 V. From V = kq/r, r = kq/V. So that r₁ = kq/V₁ and r₂ = kq/V₂. The magnitude of the difference r₁ - r₂ is the distance between the two surfaces. q the charge equals 1.63 × 10⁻⁸ C
