Is it possible to install lower version os in ipad? I am having an iPad2 with ios 6.0.1, I want to test an app which will be support for both ios 6 and ios 5.

Now, I want to install the ios 5 in the ipad.

is it possible to install the lower version than the current in an ipad?
(I am not willing to jailbreak it.)
It is possible to downgrade to iOS5. You will just have to "trick" iTunes into thinking you are restoring from one of you backups.

Just make sure to first make a backup of your current settings. Then it's just a matter of restoring from the "fake" backup(IPSW-file).

You can download an IPSW(backup file) from http://www.maclife.com/article/howtos/how_downgrade_back_ios_5