There are three different levels on which your understanding of physics may be tested. While questions on kinematics often require that you make use of some of the formulas for kinematic motion, questions on quantum physics or atomic structure may often ask just that you remember the name of a particular concept. Knowing the different ways in which your knowledge may be tested should help you better prepare yourself for the exam. Recall (20–33% of the test) These are questions of the either-you-know-it-or-you-don't variety. They test your understanding of the basic concepts of physics. No equations or calculations are necessary for these questions. They’re simply a matter of knowing your stuff. Single-Concept Problem (40–53% of the test) These questions expect you to recall, and make use of, one physical relationship, formula, or equation. This might involve plugging numbers into a kinematic equation of motion, or it might involve recalling the equation E = hf and solving for E or f. These questions test to see if you know important formulas and how to apply them. Multiple-Concept Problem (20–33% of the test) These questions expect you to bring together two or more different relationships, formulas, or equations. This could involve bringing together two formulas from the same subject—for instance, a problem in linear momentum that requires you to calculate the momentum of an object before a collision so that you can calculate its velocity after the collision—or it may bring together formulas from two different subjects—for instance, a problem that involves an electric point charge moving in circular motion in a magnetic field. These questions test not only your knowledge of physical relationships, but also your ability to integrate more than one in a complex problem. You're probably thinking that the recall questions are the easiest, and the multiple-concept problems are the hardest. This isn't necessarily true. Most people have an easier time bringing together two simple principles of mechanics than recalling the significance of the Rutherford experiment. You'll find all three types of questions throughout the test, and at different levels of difficulty. Ultimately, every question tests the very same thing: whether you've grasped the basic principles of physics.