Google is good as are the web sites you posted. One of the "problems" with certs (except the old MCM series) is that they don't necessarily teach you technique. They say that you should have X amount of experience before trying for the cert and they don't explain all the code that they might use that is common for people with the required experience. If you don't already know a particular bit of code used in the book, they expect you to study the T-SQL objects that they've used on your own. The explanation for the use of and operands of OBJECT_ID is pretty clearly spelled out in the MS TechNet entry for OBJECT_ID (the web version of "Books Online") and I recommend that you take the opportunity to study the function in depth, which will cause you to remember it much better than getting an answer to your question on a forum.

Again, I'm not saying such a thing to chastise or make fun of you. It's a recommendation to help turn you into an SQL Server Ninja instead of someone that just memorized enough to pass a test by rote (which is my other problem with certs other than the MCM series, which requires you to pass a practical exam).