The objective of Verification & Validation is that it assures that our software application meets user's needs. Both are the testing processes but the difference between Verification & Validation is that In Verification we focus on process testing and in Validation we focus on the Product testing. After completing Verification process, the Validation process starts.
Verification: Software should conform to its specification. It assures our software completely meets all the requirements. In a one line definition of Verification is:
"Are we building the product right?"
The aim behind of software verification is to detect the errors entered by an action, i.e. assure if the product of the action is as decline as it was at the starting of the action. Verification process is completed with some steps like Inspection, Walkthroughs, Buddy checks, checklists etc.
Validation: We conduct actual testing of our software product and make sure that our product is giving the output as required by the user. Validation starts during or at the completion of development phase of our product. At the time of validation, all functional and specified requirements should be satisfied. In a one line definition of Validation is:
"Are we building the right product?"
The aim behind of software validation is to announce whether the product of an action is indeed what is exactly expected, i.e. the action carried leads to the product success. Validation process is completed with some these steps like Unit Testing, Integration Testing, System Testing, User Acceptance Testing.