1)It say's that when removing files using rm command physically data is not deleting only the inode entry is removing.

2)Is it possilble to recver deleted data if know the deleted file inode number

For journaling filesystems, it is generally not possible to recover data. Which filesystem are you using?

ext3 (third extended linux file system)

I think people have said that when you delete a file on ext3, it's really deleted.

It would have been a good thing to have searched this forum and LQ because we have had a lot of threads about deletion.
Basically, if you had the data in places that would not be written over immediately and if you took measures against writing over data immediately after deleting files then there is a chance (small) of recovery (partial) using "foremost" for images and documents (search in this forum) or "grep" for text data.

You could try and comb over the drive with forensics tools but that is not a trivial task with respect to the learning curve (steep), the time you need (more than you guesstimate), diskspace (as much as you can get but at least twice the disksize on a different drive). Even then there is no guarantee for recovery so it has a discouragingly low ROI.