University:
Kentucky State University
Course:
PHY 212 | General Physics II
Academic year:

2021
Views:

303

Pages:

17
Author:

era3s4ksd

**Ch 24: Electric Potential** **Electric Potential Energy:** U = -W = -ΔU(J) **Electric Potential:** V ΔV = W/q = (Vb - Va) = Vba ΔV = W/q --- (1) **Work done by Electric Field:** W = -qΔV **Work done by an External agent:** W' = -W = qΔV ΔU = qΔV [ΔU] = [q][ΔV] J = C [ΔV] [ΔV] = J/C = Volt = V ΔU = qΔV => [qΔV] = [C][V] = J ΔU = 1e.V = 1.6 x 10^-19 J 1 eV = 1.6 x 10^-19 J **Equipotential Surfaces** Adjacent points that have the same electric potential. W_ab = -q(Vb - Va) = 0 (No work needed on the same equipotential surface) **[Image of a diagram with equipotential lines around a positive charge]** **[Image of a diagram with equipotential lines between two parallel plates]** W_ab = 0 W_bc = -q(Vc - Vb) **Calculating the electric field from the potential:** W = -qΔV F.ds = -qΔV qE.ds = -qΔV Ecosθds = -dV Eds = -dV E = -dV/ds Ex = -∂V/∂x, Ey = -∂V/∂y, Ez = -∂V/∂z **Pg 19 Page 650** |E| = ? Point = 3i - 2j + 4k = (3, -2, 4) V = 2xyz² Sol: E = Exî + Eyĵ + Ezk̂ (unit-vector notation) Ex = -∂V/∂x = -(2yz²) = -2 * -2 * (4)² = 64 N/C Ey = -∂V/∂y = -(2xz²) = -2 * 3 * (4)² = -96 N/C