Add new file

01.curriculum/01.physics-chemistry-biology/03.Niv3/02.Geometrical-optics/05.paraxial-optics/02.paraxial-optics-simple-elements/02.spherical-refracting-surface/06.spherical-refracting-surface-level-down/page.en.md

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+---
+title: 'Plane refracting surface (previous level)'
+---
+
+course : level-1 
+- or level+1 if current level = 1
+- or level-2  if current level = 4
+
+#####for parallel or other level course :
+It will be possible to redirect towards an other page in the m3p2 cursus.
+Or to write here some paragraphes separated by html from an other pages, I think.
+Or write here a completely new parallel course
+
+For the moment, please wait.