If you are considering going on to graduate school in physics or astronomy you should know that almost every graduate program in the country requires applicants to take the advanced physics Graduate Record Examination (GRE), as well as the general GRE. While it is debatable as to whether you can study for the general GRE, you certainly can and should study for the advanced physics exam. Although different graduate programs weigh the physics GRE differently, it is generally true that a high score on this exam can help your application, while a low score can hinder it.
Here's what you can do:
It is a three hour exam consisting of approximately 100 multiple choice questions covering a wide range of physics topics. You get one point for each correct answer given, and you lose 1/4 point for each incorrect answer given (this is designed so that random guessing will result in a score of zero).
Depending on your school, you may have a lot or experience or very little experience with standardized multiple-choice exams. If you haven't taken many long multiple-choice exams then practice can help, and some test-taking strategy can be important (see below).
The material on the GRE covers topics ranging from introductory mechanics to quantum mechanics. Over half of the material on the Physics GRE is covered in courses taken in the first two years at most colleges (courses such as General Physics I & II and Modern Physics). You may not be as familiar with the material from classes you took several semesters ago. Reviewing the material in all of your courses will also help give you a broader picture of each topic, and you may learn some things you missed the last time you went through that material.
Most people do not finish all 100 questions. You should read the entire test first (or at least a lot of it) and classify questions for later. Then come back and answer them. You only have 3 hours, and if you spend a lot of time on a hard question you may not have time to do later questions that would have been easy.
One way to do this is to quickly read each question and give it a rating - E for easy, M for medium, H for hard. (Or you can use smiley faces and frowny faces, stars, thumbs up or thumbs down, or whatever symbols work for you.) Try not to answer the Easy ones first. Then go through and do all the Easy questions first. If you find one harder than you thought, change it to Medium or Hard and move on. When you finish the Easy questions, go back and do all the Medium questions, saving the Hard questions for last. This insures that you get all the points you really deserve, and your extra time (if any) is reserved for the hard questions that need it.
Alternatively, you can answer the Easy questions when you first get to them but don't start on the Medium or Hard questions until you have finished all of the Easy questions.
It may take some discipline to not do the Easy questions first, but you really want to read the entire exam first. If you get nervous about taking tests, or at least this test, then knowing what you are up against can put your mind somewhat at ease. More importantly, your brain's memory will be accessing information about some of the Medium and Hard questions even as your brain's executive function is working on other problems, just because you read the questions ahead and saw what they involve. Instead of strugging to remember things, you will have information you need when you get to those harder problems.
Another important thing to remember is that each question is only worth 1 point out of 100, so it is not worthwile to spend too much time on any one question, when there may be many others you can easily get right.
You lose 1/4 point for each wrong answer, so that pure guessing would give you a score of zero. But if you can eliminate several answers and want to guess from among the rest, the odds are in your favor. Given this you should also...
On many questions on the physics GRE you can eliminate one or sometimes more than one possible answers because they do not have the right units, or because they don't have the right order of magnitude. Other answers can be eliminated based on simple scaling arguments. For example, if you double the size of one thing and know that something else should double, but it doesn't for one or more of the answers offered, then you know that they are wrong.
Students who have done this have done well on the GRE. It's not as hard as it sounds if you do a little bit every day, and in fact if you do it that way you will learn more than if you "cram".