Consider a $3-$m$-$diameter spherical tank that is initially

filled with liquid nitrogen at $1$ atm and $-196\backslash$deg C$.$ The tank is

exposed to ambient air at $15\backslash$deg C$,$ with a combined convection

and radiation heat transfer coefficient of $35($W$)/($m$^(2))*$Kk$=0\mathrm{.}035($W$)/($m$)*$K $0\mathrm{.}00005($W$)/($m$)*$K$.$