Hi everyone…
M new to root and trying to derive line plots from theTREE in root file using Geant4.
Any help will be highly appreciated. 
What to you mean exactly by this ? you have a TTree and you want to Draw it as a line plot ?
Yes
I have been trying to make line plots using this. I just want to convert the histograms that I get into line plots in root only.
You can try to draw the TTree with the option L or get the TTree variables in arrays and draw them as TGraph as shown in this tutorial .