I use C#, .net 4, Entity Framework and SQL Server 2008 R2 in a project.
I have no familiarity with backup and restore from database by Entity Framework. Please help me to write restore and backup code in Entity Framework
Entity Framework is an ORM - object-relational mapper - designed to handle interactions with single entities and/or short lists of entities. It's neither designed for bulk operations, nor is it a server admin framework. So no - I don't think you can do this using Entity Framework - that's not its job.
Use an appropriate tool for the job! Either use SQL Server Management Studio to handle backup/restore - or if you must do it programmatically, use the SMO (Server Management Objects) which is intended for exactly these kinds of jobs