after buying a licence, if i uninstall rhino then is it possible to recover or i have to buy a licence again ???
If you add your license to Cloud Zoo you can use it again, no need to buy.
Your EDU license will be owned by you and not limited to a single installation.
You can replace your computers and/or change the method of licensing you use; single-computer exclusively (no internet required), or Cloud Zoo Personal so it can be used on all the computers you own, but it does require an occasional Internet connection.
You can also use your license for commercial work when you finish school.
You can not transfer ownership or sell your EDU license.
i have choose the option either single computer or cloud personal at the time of purchase right ??
No. The license is the same either way.
The choice is the method you use. There is no difference in price and you can change it later if your situation changes.
When you run Rhino the first time, you’ll be asked for your license key.
Here’s a link to the details.
It also includes a link to a wizard that helps you choose what will fit your needs the best.