The Physics GRE
Here is some information and general advice for the Physics GRE exam. If
you have additional advice/resources that you'd like to share with Stanford
SPS, please e-mail Flip (
The GRE Physics Test, along with the GRE General Test, are the two standardized
exams you are required to take throuh ETS to apply to most U.S. graduate
programs in physics. The source for official information is the ETS
When to Take It?
The GRE Subject Tests are given three times a year in November,
December, and April (check the official
ETS site for dates). ETS takes about a month to process scores and most
graduate school applications are due in December and January, so November
is the de facto "last chance" to take the Physics exam.
The December test usually conflicts with Stanford's final exams, anyway.
If you can adquately prepare, taking the April exam is ideal since
you don't have to study for the GRE while preparing grad apps and, in the
worst case, can "fall back" on the November exam if you don't
do as well as you'd wanted.
GRE subject tests are paper-based multiple choice exams that are administered
at certified testing centers on Saturday mornings. As of the 2005 exams,
the closest testing centers to Stanford were Santa Clara
and San Jose. You'll probably need a ride to get there.
The exam is 100 questions and three hours long.
The exams are $130 to take and you can list up to four
scholarships/schools to send your scores to for free (it's in your best
interest to do this and to keep track of which schools you've sent scores
to!). Additional score reports are $15 per report plus a $6 phone service
How to Study
The GRE Physics test is not likely going to be like any other physics exam
you've had while you've been at Stanford. While the test is about as long
as your standard in-class final, you're not allowed to have any notes or references.
Some people interpret this as a requirement to memorize every formula one can get one's
hands on, but this isn't necessarily the case. Also, the exam is composed of 100 multiple
choice questions--this means you need to identify the correct answer (by whatever means
you can) as quickly as possible.
The best way to prepare is to spend a quarter (or most of a quarter) working
with a study group of physics colleagues. You should focus almost exclusively
on the official practice exams, no other source of problems seems to have
representative topics of types of questions. The study group will provide
your framework for working out problems, keeping on-schedule (and do keep
a strict schedule of practice exams), and providing encouragement.
Official Practice Exams
ETS has the 2001 test available online through their webpage. Additionally,
there is an out-of-print ETS
book with the 1986, 1992, and 1996 exams. This is being sold at a ridiculous
price online, but it is on reserve in the physics library and can be checked
out from the physics main office. However, one can do even better than this,
the Brandeis physics department appears to have all
four of these exams available as PDFs for free online.
These exams contain the types of questions that are the most representative
of those on the actual test. The conventional wisdom is that the 2001 exam
is the most similar to current tests, while the remaining exams (GR9677,
decrease with difficulty in reverse-chronological order. The '96 exam tends
to have more order of magnitude estimation and the '86 exam tends to have
more questions that can be eliminated by dimensional analysis.
You should be sure to take all of these exams with enough time to go over
them before the test date, with at least one exam under test conditions
and ideally spending time on your own repeating all the questions that you've
What You Need to Know
(..."and how well you need to know it.") Perhaps the first thing
you should look at after organizing your study group is the breakdown of
test questions on the ETS website and on the first few pages of the practice
tests. Make sure you are familiar (to some degree) with the sub-topics in
each of the main branches of physics tested. It's not likely that you'll
be an expert in each of the "specialized topics" but you should
be relatively fluent in the subjects that constitute 10% or more of the
questions. Here's a rough account of the level at which different topics
need to be known:
- Classical Mechanics (20%): Most of the questions are
at the 40-series level, though you should be familiar with the basics
of the Lagrangian and Hamiltonian formalisms. Some Physics 110-level questions
on central potentials may show up. You should be more than adequately
prepared reviewing out of a book like Marion & Thornton for the advanced
topics and your favorite freshman mechanics book for the rest.
- E&M (18%): The Physics 120 series provides all
of the background information necessary. Most calculations are at the
freshman-physics level, though you are expected to know quantitative relations
for more advanced topics (e.g. how does the total power radiated by a
point source depend on charge?). Griffiths should cover anything you need
to know, but most questions are at the level of the 40-series text.
- Optics and Wave Phenomena (9%): You should be fine
with the 20- or 40-series texts for these topics.
- Thermodynamics and Statistical Mechanics (10%): There
will be more exams from freshman-level thermodynamics rather than Physics
170-level statistical mechanics. That being said, it doesn't hurt to know
what a partition function is and how it works. Again, the 40-series text
should suffice except for a basic understanding of statistical mechanics
- Quantum Mechanics (12%): If you've taken the Physics
130 series, you'll be insulted at how simple most of the quantum questions
are. Most questions are at the level of the Physics 70 text.
- Atomic Physics (10%): The best reference for the atomic
physics topics is probably the Physics 70 text (I found Beiser, which
is what I used for 70, especially useful). Don't be overly concerned by
these questions just because you haven't taken an "atomic physics"
- Special Relativity (6%): Knowing how to do calculations
at the Physics 70 level is a must.
- Laboratory Methods (6%): Now you can check how much
you picked up from Physics 105 and 107. You'll have a couple to a few
questions with circuit diagrams, and possible a question or two on lasers,
oscilloscopes, and statistics. The circuit diagrams are at the basic E40
- Specialized Topics (9%): There isn't too much you can
do here. If you've started thinking about what you want to study in graduate
school or have spent a summer or two doing research, chances are that
you have some background in one or two of these topics. It's not worth
it to pick up a book on some other topic (say, astrophysics if you're
a condensed matter person or vice versa) with the intent to read the first
5 chapters. Instead, see what kinds of questions pop up regularly on the
practice exams and read up on certain topics (always starting with the
easiest expositions at a Physics 70-level text!) as you have time.
A good "extended" version of a standard freshman physics textbook
(such as the latest extended edition of Halliday and Resnik) tends to be
useful to have handy as you're going over problems. (The "extended"
sections contain most of the modern physics you'll need.)
Some further (somewhat redundant) bits of advice:
- Don't waste your time with any other GRE Physics test prep material.
The REA GRE Physics textbook is notoriously bad for preparing for the
exam--it has a reputation for unrepresentative questions that are riddled
with errors. Four practice exams are plenty to comb through a couple of
times to make sure you understand every question.
- Set a study group schedule and stick to it. Make studying
for the GRE Physics a priority. Consider meeting once a week for a few
hours. Decide if you want to spend your time together reviewing questions,
checking strategies, or doing sections of an exam; but use each other
as resources for alternate points of view. Agree on dates when the entire
group should have completed each practice exam and when exams should be
reviewed. Learn (perhaps from others in your group) how to solve the questions
- Solve questions quickly. You're not trying to write
down an elegant proof for any of these questions. Each question shouldn't
require much more than a minute's worth of thought and computation to
complete. Exploit process-of-elimination, dimensional analysis, order-of-magnitude
estimation, and any other clever tricks you can pull off. If your method
of doing a problem requires doing a nontrivial integral or anything that
requires more than a minute's work, then you're looking at it the wrong
- Memorize equations sparingly, but as necessary. The
better you understand the physics of a subject, the fewer equations
you'll have to memorize and the easier it will be to memorize meaningful
equations. For the most part you won't be quizzed on factors of 1/2 (unless
it's a well known result, such as the vacuum energy of the quantum harmonic
oscillator), so it's more important to know how one quantity depends on
- For some reason, positronium is important. Positronium
tends to show up in one form or another, understand it at the level of
Physics 70 (i.e. reduced mass, how its energy spectrum differs from hydrogen,
- Guess intelligently. You're penalized a quarter of
a point for every wrong answer, so you can maximize your total scores
by playing the intelligent-guessing game (that you once used on the SATs,
and more recently used to solve ODEs).
- Use what you've got. You are given a table of information
including formulae for common moments of intertia and fundamental constants.
Learn to use these in clever ways to make order of magnitude estimations.
Below is a short list of useful links:
Some things to remember on test-day: eat breakfast, bring a snack and something
to drink. Three hours is a long exam! Also, be mindful of your own body
and don't drink your entire bottle of water right before the test starts.
You're not allowed any restroom breaks in the last half hour of the exam.