SalesForce Technical Questions.............

Technical Questions
1)     What is Apex?
2)     What is VisualForce?
3)     What is an S-Control?
4)     What is the difference between Visualforce and S-Control?
5)     What are recursive triggers? How can we avoid the recursion problem?
6)     What are apex governer limits?
7)     Do governer limits apply to sandbox instances?
8)     What are recent release features?
9)     How do you use actionFunction tag?
10)   What is the difference between actionFunction and actionSupport tags?
11)   What is actionPoller?
12)   What is the difference between ISNULL and ISBLANK?
13)   How do you do FileUpload using visualforce?
14)   What is appExchange? How can I host my application on appExchange?
15)   What is batch apex?
16)   When will you use batch apex and what is the best practice?
17)   What is apex scheduler?
18)   What are webservice callouts?
19)   What are wrapper classes?
20)   When do we use wrapper classes?
21)   How do you hide header and side bar on visualforce page?
22)   What is the difference between standard and custom controller?
23)   What is controller extension?
24)   How do you read parameter in visualforce page?
25)   How many dependent drop downs can be put in visualforce page?
26)   What is the maximum size of the PDF generated on  visualforce attribute renderAs?
27)   How can we check the objects accessibility on visualforce page?
28)   How many rows are returned by a list controller?
29)   What is custom component?
30)   What is assignTo attribute and what is its use?