Simple question, I make an application for my phone (android froyo). Is it will run on android froyo tablet ? Or I must make some modification to make it work on tablet ?
Simple answer: It may run on the tablet - try.
Not so simple answer: It depends on whether you use some features of the phone and whether those features are available in your tablet. For example, if your tablet does not have GPS and you are developing location aware applications, that obviously is not going to work. Another thing to take care of would be the usability of the application. Your UI would most probably be designed with the phone's form factor in mind. That may not look exactly appealing on a large screen device like the tablet.