This lecture covers the evaluation and application of magnetic fields as vector fields and field lines, the Lorentz force, cyclotron motion of charge carriers, Ampère-Laplace law, force between conductors, Ampère's and Gauss's laws for flux of magnetic fields, and magnetic dipoles. It also discusses the force between two straight conductors, including the force on conductor 2 by the field of conductor 1, assuming wires in the x, z plane, parallel, and infinitely long. The lecture concludes with a question on calculating the force between two very thin parallel Cu wires.