Fig. 2. The temperature-mass depth variable in logarithmic scale for model =15000K and log g=4.0. Solid line- LTE model with n(He)=0.1 and dotted line- NLTE model, dashed line-NLTE model and n(He)=1., dash dot dot dot line-Kurucz LTE model model and n(He)=0.1. The asterisk stands for depth point with T=T_eff.