I'm currently taking a normal physics class and I want to know if it will that be enough to prepare me for the SAT II Physics subject test? Are there any concepts on the subject test that aren't taught in a normal physics curriculum?
"The Physics Subject Test assesses your understanding of concepts from one year of introductory physics on the college-preparatory level, as well as reasoning and problem-solving skills derived from lab experience."
Based on this statement, you should be fine taking the subject test after a regular introductory physics class. Classes at each high school are different, though, so I'd recommend that you check the link above to get an idea of which concepts you can expect to see on the test. Notice that around 80 percent of questions on the Subject Test deal with Mechanics, Electricity and Magnetism, and Waves and Optics. It's centered around the most essential topics in physics, and all the questions are multiple choice, so it's very unlikely that you'll be out of your depth.
However, I want to point out that just because you can take the test after your current physics class doesn't necessarily mean it's the best option. If you're currently a sophomore and are planning on taking AP Physics your junior year, I would suggest waiting until after the AP class to take the Subject Test. Studying for the AP test will cover all your bases for the SAT Subject Test as well, and you'll be so prepared that it will seem much easier.
If you're interested in learning more about what questions are actually like on the Physics SAT II, you can [consult the College Board's guide to all the Subject Tests, which includes sample questions and more details on the format and content of the test.]