I have taken quite a few Core tests at different sites and I was one of the first to take the first ever core test at SRS. While the questions all come from the objectives, they are asked in such a way that sometimes it is difficult to know what they are getting at. The questions are tricky so pay attention to what the question is asking. For instance the 6CEN question usually gives the energy levels in Kev instead of Mev, so make sure and convert to Mev or you will be wrong. The tests are not hard as long as you take your time and read the whole question before trying to answer it. Good luck.