The paper should go be 2.5 to 3 pages long without Abstract or References page counted, in a single space, 12 point font. It should have an Abstract (introduction/summary of our paper) on the first page (that's not part of your 2.5 or 3 pages) and a Reference page at the end (that's also not part of your 2.5 or 3 pages).

Now, the topic of the paper. What should you write about? Anything connected to physics, technology, astronomy, biophysics, medical physics, engineering, sci - fi movies, time travel! As you can see, it's a very broad subject.