1. What is Apex ?
Ans: It is the in-house technology of salesforce.com which is similar to Java programming with object oriented concepts and to write our own custom logic.

2. What is an S-Control ?
Ans: S-Controls are the predominant salesforce.com widgets which are completely based on Javascript. These are hosted by salesforce but executed at client side. S-Controls are superseded by Visualforce now.

3. What is a Visualforce Page ?
Ans: As I said in the above answer, S-controls are superseded by Visulaforce, Visualforce is the new markup language from salesforce, by using which, We can render the standard styles of salesforce. We can still use HTML here in Visualforce. Each visualforce tag always begins with “apex” namespace. All the design part can be acomplished by using Visualforce Markup Language and the business logic can be written in custom controllers associated with the Page.

4. Will Visual force still supports the mege fields usage like S-control?
Ans: Yes. Just like S-Controls, Visualforce Pages support embedded merge fields, like the {!$User.FirstName} used in the example.

5. Where can I write my Visualforce code ?
Ans: You can write the code basically in 3 ways. One go to, setup->App Setup->Develop->Pages and create new Visulaforce page. While creating the Page, You will find a salesforce editor. You can write your Visualforce content there. Or go to Setup -> My Personal Information -> Personal Information -> Edit check the checkbox development mode. When you run the page like this, https://ap1.salesforce.com/apex/MyTestPage. you will find the Page editor at the bottom of the page. You can write you page as well as the controller class associated with it, there it self. OR Using EclipseIDE you can create the Visulaforce page and write the code.

6. What is difference in ISNULL and ISBLANK?
7. How many types of Reports I can create in salesforce. what are they?
8. What is dashboard. How it is created ?
9. What is Page Layout?
10. What is the Related List?
11. What is the difference between Page Layout and Related List?
12. What is mini page lay out?
13. How do I change the home page layout?
14. When you can’t add Time dependent action in Workflow rule?
You can’t add time-dependent actions to a rule if you choose Every time a record is created or edited.

15. are the types of email templates available in salesforce.com?

HTML with Letter Head
Custom HTML
Visual force