Electric Field Due To An Infinitely Long Straight Wire

Electric Field Due To An Infinitely Long Straight Wire — the NEET Physics formula with its derivation, variables, validity constraints and worked solver.

Electric Field due to an Infinitely Long Straight Wire Valid for points outside the wire where the length of the wire is significantly larger than the radial distance 'r' (infinite approximation). Assumes vacuum or air medium. Construct a cylindrical Gaussian surface of radius r and length L coaxial with the wire. Apply Gauss's Law: Flux = q enclosed / epsilon 0. Due to symmetry, E is radial and constant over the curved surface area (2 pi r L). Flux through flat ends is zero. Equate: E (2 pi r L) = (lambda L) / epsilon 0. Solve for E. r > 0 Wire must be straight Charge distribution must be uniform Confusing the 1/r relationship of a line charge with the 1/r 2 relationship of a point charge. Assuming the field exists inside a conducting wire (it is zero in electrostatics). Applying this formula near the ends of a finite wire.