Hello kartik,
As we know Scope is a special memory allocation to a particular directive or controller.
A directive or controller can have inherited scope in which the scope of child is defined under parent so child can have access to its data member as well as its parent data member
However, Isolated scope is completely different from inherited scope.
In isolated scope, when a directive use a special attribute called "Scope" in its directive definition then the directive have its own scope which is completely independent from the parent scope. The directive Scope and parent scope has no communication between them.
Example of Isolated Scope with code give below:
From above, it is clear that the controller named sample has its own scope and the message directive has its scope which is independent from each other.(This is not in case of inheritance scope).
However, in order to communicated between parent scope and isolated scope we can use Scope parameter.(Don't know what scope parameter is!! refer Scope parameter).