I'm new to Ruby On Rails and I want to know which is better to use for work with it. Windows or Linux. I've never worked with Linux before but I heard It's better to work with it. Is it necessary for someone like me to install linux or I can use windows and the results will be same with linux?
If your current dev machine is running Windows, and you don't have access to a Linux environment right now, don't let that stop you from getting started with Rails. Definitely, definitely, definitely install the DevKit first thing (if it's not included in RubyInstaller yet). See https://github.com/oneclick/rubyinstaller/wiki/Development-Kit for that.
If you get deep into Rails development, or even start doing it for a living, you will inevitably drift towards using Linux on your dev machine. The problem is not Rails, but the many binary gems which are difficult or impossible to install on Windows.
The most popular Ruby library for manipulating images (ie. generating thumbnails) is RMagick, but trying to install it on Windows is enough to make a strong man cry. Paperclip is very nice for dealing with images and other attachments, but it is also a problem. Then there is a popular JSON parsing library which is also problematic on Windows. Unicorn (a popular Rails server) won't run at all on Windows, and Thin (my favorite) may also give you headaches. And so on, and so on.
You can get pretty far with Rails development on Windows these days, but at times you will find yourself having to test code on a remote server, rather than locally, and it can waste a lot of time.