Is there a way to prevent the second monitor to turn black when an application in the first monitor is made full screen? I have this problem in Mac.
Yes there is (And if you use a Mac, I also believe that there is enough information on the issue to answer the question).
Just go to System Preferences > Mission Control and check the option that says "Displays have separate Spaces".
That solves the issue on one monitor going black when there is an app on fullscreen mode in the other.