In wordpress is it possible to have different widgets on different pages,
I mean, I am having a form widget which has to be just displayed on posts page, it should just display on single.php
Is this possible? Is their any plugin for this?
There are two options:
You can also use a combination of these methods when you need to manage sets of widgets over a variety of different areas.
Well, I may be wrong, but why can't you just create different sidebars for single and posts page? That's easier and doesn't require plugins.