In this Physics video in Hindi we explained band theory of solids for the chapter "Semiconductor" for class 12. In this video we explained how the energy level split for two close hydrogen atom and how hydrogen is diatomic and helium is not. Click here to visit the playlist on this chapter https://www.youtube.com/playlist?list=PLW0F47OesfFNg35fRk7ywRO2Vb6dlMEzE