an infinite straight wire carrying I in the z direction is: Using Ampere’s Law to solve problems If we have a symmetric problem, such that the direction of is known and is constant over a chosen path, then: Therefore: H = I / pathlength Example: Consider an infinite current sheet with current density . volume current density Jin the +xdirection. What is the magnetic field both inside and outside the slab? First, we need to find the direction of the field. From the Biot-Savart law, we know the field must be perpendicular to the current, so there can be no field in the xdirection. Now if we consider a thin line of current parallel

Current Sheets A current sheet is electric current flowing along some 2D surface. Thanks to the Ampere Law, current sheets cause discontinuities of the magnetic field B(r). That is, as r approaches the same point on the current sheet from two different sides, the magnetic field B(r) has different limits.