Determine the current $\backslash ($ I $\backslash )$ in the coil and the magnetic force $\backslash ($ F$\_\{$m$\}\backslash )$ exerted on the movable part to keep it suspended in air at $\backslash ($ l$\_\{$g$\}=0\mathrm{.}01\backslash$mathrm$\{$~m$\}\backslash )$ from the immovable part if $\backslash ($ N$=120\backslash )$ and the energy stored in the magnetic field is $1\mathrm{.}5$ mJ $.$ Ignore any leakage and fringing. $($Hint: First, draw the magnetic equivalent circuit and then find the total reluctance.$)$