Using Van der Waals equation $,$ find Joule Thomson inversion temperature of nitrogen at $5$ MPa and $10$MPa $,$ a $=136\mathrm{.}69$ KPa$($m$3/$KPa$)2,$ b $=38\mathrm{.}64$x$10-3$ m$3/$kmol$,$ R $=8\mathrm{.}314$ KJ$/$Kmol K