# Physics Graduate Record Exam

### What is the GRE?

The GRE, or Graduate Record Exam, is the generic name for a number of multiple-choice style exams administered by the Educational Testing Service. These are the same people who administer the SAT and Achievement exams you likely encountered in high school. There are two different kinds of GRE exams that you may have to take: the general GRE, and the subject GRE. The ETS maintains a GRE home page that has a lot of relevant information. You can easily get practice materials from them, both free stuff and copies of former exams. GRE Home Page.

### The General GRE

The general GRE consists of three parts: verbal, mathematical, and analytical. The verbal and mathematical parts are quite similar to the SAT in material covered, style of questions, and level of difficulty. The analytical part consists of logic questions and puzzles. Most Grinnell physics majors do not have much difficulty on the general GRE, although non-native speakers of English may find the verbal section challenging. In any case, you may find it beneficial to take a practice exam or two before the big day.

It is possible to take the exam either in written form (by filling out bubble sheets) or on the computer. The written exam is administered three times a year, in April, October, and December at 8 am. Typically you need to register by mail at least six weeks in advance of your exam, and you don't find out your scores until about a month after the exam. The computer-based exam is available much more frequently, and you can see your score immediately, but it has some disadvantages you should know about.

In the written form, the exam has two sections of each kind (verbal, mathematical, and analytical) plus one extra experimental section of some kind so that ETS can gather statistical info on new test questions. Each of the seven sections takes half an hour to complete, so the whole exam takes three and a half hours.

In the computer-administered form, the exam takes only half as much time. You answer about 27-33 questions in each of three sections. The computer decides which questions to ask you next based on the correctness of your previous responses. If you keep answering questions correctly, the computer will ask you harder and harder questions until you get one wrong. On the other hand, if you answer hard questions incorrectly, the computer will start pitching you easier ones. Because of this "customization" of the questions, you cannot go back and change any of your answers to previous questions. Another caveat to keep in mind is that, although this exam is offered frequently, you cannot take the computer-administered exam more than once in a six-month period.

### The Physics Subject GRE

The GRE Subject test is an extremely important factor in determining where Grinnell students are admitted for graduate study in physics. It is similar to an achievement test, but it is three times as long and much harder. GRE Subject tests tend to cover all of the curriculum that is usually taken by an undergraduate majoring in the subject. These tests are available only in paper form and are administered at 2 pm on the April, October, and December test dates.

The physics subject test covers all of the material from all of the courses offered in the physics major, including electronics, quantum mechanics, and statistical/thermal physics. They also ask questions about typical physics labs and about famous experiments. You have 170 minutes to solve 100 physics problems with multiple-choice answers. You may NOT use a calculator on the exams. You are NOT given any equation sheet. You just have to know all the equations you might need to solve any problem in physics.

The following list summarizes the topics covered in the exam and their relative weighting. Also listed are the Grinnell College courses that are most relevant to each topic.

- 20% Classical Mechanics (PHY 131 and 234).
- 18% Electricity and Magnetism (PHY 132 and 335).
- 9% Optics and Wave Phenomena (PHY 337).
- 10% Thermo and Stat Mech (PHY 232 and 456).
- 12% Quantum Mechanics (PHY 232 and 437).
- 10% Atomic Physics (PHY 232 and 437).
- 6% Special Relativity (PHY 232).
- 6% Laboratory Methods (PHY 131, 132, 232, 337, and 462).
- 9% Specialized Topics, e.g. nuclear, particle, condensed matter, astrophysics, math methods, computational, ... (various courses, esp. PHY232).

Most of the questions on the exam can be answered by somebody who knows first and second year physics really well. However the rapid pace of the exam requires some getting used to. There are some strategies you can follow to improve your chances of getting a good score on the GRE.

### Cunningham's Strategies for the Physics Subject GRE

- Consider taking PHY 456 (Thermodynamics and Statistical Physics) in the spring of your third year.
- Get the general GRE out of the way by taking it in the spring of your third year, or by taking it electronically in the fall of your senior year.
- Invest an hour or so in reviewing first-year and second-year physics each day during the summer after your third year. Start out by reviewing Halliday, Resnick, and Walker, and then go on to your modern physics book. Go through each chapter — including the ones that weren't covered in class — memorize the important formulas, and practice solving problems in the back of the chapter until you can do them in under a minute. You may find flashcards useful for memorization.
- In the fall of your senior year, start taking practice exams. Actual copies of the physics subject GRE are best for practice, but there are only two available. You can get a book containing the two exams in the physics seminar room, or you can get your own directly from ETS (but order early because it may take a while to arrive). Be sure to time yourself while you're taking the practice exam to get used to the rapid pace.
- Take the exam in October. That way you can study some more and repeat the exam in December in case you have trouble the first time.