Two infinitely long parallel wires having linear charge densities λ1 and λ2 respectively are placed at a distance of R meters. The force per unit length on either wire will be
When two infinitely long parallel wires with linear charge densities λ1 and λ2 are placed at a distance R, the force per unit length on either wire is given by the expression (2kλ1λ2)/R, where k = 1/(4πε0) is the Coulomb constant. This formula arises from the application of Coulomb's law and the principle of linear superposition.