Btw I am obtaining all these equations from chapter 5 of Griffiths text. Lorentz force law is: Fmag = ∫I(dI x B) Does this give the force on a current carrying wire due to an external magnetic field? (i.e. has nothing to do with own wires magnetic field) I think the answer is yes since the wire can really exert a force on itself. Also I am confused about the dI term. Is this as small segment of current in the wire? (the one we are calculating the force on) secondly, Amperes law in integral form is: ∫B . dI = Ienc*μo (the period is the dot product) I understand the idea of this integral, but again I am confused by the dI term. I know the LHS of the above equation is just the magnitude of B time the length of the loop enclosing the current. It seems that dI is a segment of the loop enclosing the current, but if dI is a segment of current (as I assumed for Lorentz law) I think I might be missing a piece of this puzzle.