For further reading about Phase Rule, Please click on the link given below ......
http://vedupro.blogspot.in/2013/05/ph...
PHASE
Phase is defined as Homogeneous and Physically distinct part of a system which is bounded by a surface and is mechanically separable from other part of the system.
COMPONENT
The number of components may be defined as the minimum number of required chemical constituents using which compositions of all the phases can be defined.
DEGREE OF FREEDOM
The degree of freedom may be defined as the minimum number of variables (P,T & C) which must be specified to describe all the phases of the system.