What is this mode and how do i get out of it? Was following blender guru's tutorial(Part 7 lvl 1) to split the screen,and when i joined the split i accidentally joined this view to my colored view.Now i can't get out of this view.When i render the image ,it stills show colour previously used.
I assume you're talking about Rendered View. Just click the button I marked in the screenshot.
Here is some more information on what these four buttons do.

I hope this helps.