Well, the only problem with the OP's exam is that it may be hard to distinguish those who are able to use their knowledge, and synthesise a solution, to those who got lucky. The problem with getting lucky is that in the actual HSC, there's much less chance of getting lucky. One of the perks of physics is the marking criteria, they may be looking for specific things that get that extra mark. For example, I know a former student who never lost more than 1 mark for any one question in their physics exam, but those 1 marks accumulated and subtracted a fair bit from the total. I know another student, who, got lucky in his half-yearlies physics exam because he happened to do the same question from a past paper exam that the half-yearlies asked. He went up to me and said, "I know what they were looking for, I remembered the marking criteria and it said to include X,Y, and Z!". He didn't know what to include the first time around, but got lucky when it was assessed. The only disadvantage with this is that, as a result, his critical thinking skills, required to answer HSC questions later on, was not as developed as it should be.