Question

When this 'L'-shape is rotated about the origin (0,0) by 90° counter-clockwise, which one of these would it look like?

Answer 1

The "L"-shape would look like it fell backwards and was laying on the ground. The little leg of the L would be pointing up into the air. 

A 90 degree counter clockwise turn means that it rotates left around the origin. It turns one half of half a turn, or 90 degrees.