A limited subject can be handled within the assigned length of the paper. The teacher may assign one or require you to choose one from a list. Or, the teacher may provide model subjects to help you find one of your own.
Research papers are generally required to fall within the subject matter of the course in which they are assigned, but teachers in composition courses sometimes permit students to write about whatever they choose, so long as the subject is clearly enough defined.
In uncertain cases, you should consult with the teacher to determine whether the subject is too broad, too limited, or is of suitable scope.
It's a good idea to consult with your teacher anyway, just to be sure you're on the right track.
The limited subject you choose will usually not be the topic of the finished paper. Your conception of the subject should change as you go along and your way of stating it will emerge toward the end of your work. All you need for now is a reasonably clear idea with which to begin.
Once you have a limited subject, click below.