Concept of Hibernate Mode

When you switch your laptop to hibernate mode, you are turning your computer off but saving everything you had up last while the computer was on. So when you turn it back on, the laptop will load up all the last work or whatever windows you had open before you enabled hibernate. As we all know when we restart our system, all the data that was present in RAM get vanished.
So how exactly this hibernate mode loads all the last work you had open before. In hibernate mode the current state of the system is saved in file called hiberfil.sys in your C drive and size of this file is around 1.5 Gb. Bydefault this file is invisible, if you want see this file
Goto folder options >> view >> choose show option and uncheck hide O/S protected files.
But I recommend you should always hide your O/S protected files.
So when you will choose hibernate mode your system will power down. When you will turn the system power back on, the saved information is read from the hiberfil.sys, restoring the last used settings.