1. Explain your roles in the project.

https://www.infallibletechie.com/2014/10/what-are-all-roles-and-responsibilities.html

https://www.infallibletechie.com/2014/11/roles-of-salesforce-administrator.html

2. Any custom functionality have you developed?

https://www.infallibletechie.com/2012/06/auto-complete-text-box-in-salesforce.html

https://www.infallibletechie.com/2012/06/dynamically-adding-rows-in-apex.html

3. I have three text fields.. say first name, middle name and last name. I want to make them unique. How can we do it using admin?

Create a field with Unique attribute. Use Field Update WF to update this field with the concatenation of First Name, Last Name and Middle Name.

4. I have two page layouts p1 and p2, 2 profiles prof1 and prof2,  have 3 field f1, f2 and f3. For prof1 I have p1 and f1 f2 on the page layout .. prof2 has p2 layout and f3 field. Now all the three fields have validation rules. When prof2 user is trying to create a record and save will f1 f2 validation rules get fired ?

Yes, they will get fired.

How can we prevent the f1 and f2 validation rules from executing for the prof2 user?

In the Validation rule check the User’s profile.

5. Have you worked on workflows approvals? If so, what is it?

https://www.infallibletechie.com/2015/10/approval-process-salesforce.html

6. What are different workflow actions?

https://www.infallibletechie.com/2015/10/what-are-different-workflow-actions-in.html

7. How are workflow actions triggered? i.e., what are the conditions?

https://www.infallibletechie.com/2015/10/how-are-workflow-actions-triggered-in.html

8. What is the difference between when created edited and created any time it’s edited to subsequently meet criteria in Workflow Salesforce?

https://www.infallibletechie.com/2015/10/what-is-difference-between-when-created.html

9. I have an object and a pick list STATUS. In that values are open, close and win. I want to send a mail every day till the status is open. How can u do that using workflows?

We have to develop batch apex and schedule it daily.

10. Triggers and what all the situations they get fired (events )

https://www.infallibletechie.com/2012/08/when-to-use-triggers-in-salesforce.html

11. What are collections?

List, Set and Map

12. What is the difference between collections and primary data types?

Collections can hold a group of data.

13. What is Viewstate?

https://www.infallibletechie.com/2012/09/view-state-in-salesforce.html

14. What is required for SOAP API?

WSDL

15. What are all the relationships in salesforce?

https://www.infallibletechie.com/2015/10/relationships-in-salesforce.html

16. What is the difference between Lookup and Master Detail relations?

https://www.infallibletechie.com/2013/02/difference-between-lookup-and-master.html

17. I want to change Master Detail to Lookup.. what are the considerations?

We have to delete the Roll up Summary Fields.

18. How do you write roll-up summaries for example say I have an amount field on the child records and it rolls up to TOTAL AMOUNT when it was Master Detail relation. Now its LOOKUP so how to handle this.

1. Use trigger 
2. Use App Exchange product

19. Order of execution

https://www.infallibletechie.com/2013/04/order-of-execution-in-salesforce.html

https://www.infallibletechie.com/2015/05/order-of-execution-in-visualforce-page.html