A very large and thick sheet of conducting material carries a non-uniform current density  $\overrightarrow{J}=J_0{\left(\frac{x}{d}\right)}^2\widehat{y}.$ The slab extends form x = –d to x = d, and is infinite in y and z.

The magnetic field at  $x=\frac{d}{2}$  is  $\frac{{\mu }_{0}Jd}{24}.$

The magnetic field at  $x=2d$  is  $\frac{{\mu }_{0}Jd}{3}.$

The magnetic force per unit area on the right half of the sheet is  $\frac{{\mu }_0{J}^2{d}^2}{18}.$

The magnetic force per unit area on the right half of the sheet is  $\frac{{\mu }_0{J}^2{d}^2}{9}.$