To wonderful physics students everywhere (not just at CWRU!):

Through the years we have developed flashcards to help students prepare for the physics advanced GRE. The intention is to provide as best we can the background material, including those formulas you need to recall quickly because you don’t have time to derive them. Our motivation was to address the omnipresent problem of students forgetting material, even forgetting basic formulas and descriptions (no cheat sheets in life!). More than that, students need to learn how to read more carefully, to make simple math calculations and estimates without automatically reaching for a calculator (and woe to us if we mispunch a key and not know what to expect as a reasonable answer), and to deal with no partial credit if your answer is not right! A different sort of critical thinking is practiced here and not always in our classrooms. And practice working more quickly is never bad.

By now thousands of students have benefited from our effort, most of them outside of our own Case Western Reserve community.


Presently, standardized tests are in a state of flux. While the physics GRE was not required during the pandemic, it appears now the top ten or twenty schools are generally accepting the pGRE score, at least optionally, to help you in your applications to grad school. (Astronomy grad schools don’t require it in general.)

In addition, the Physics Test is now shortened to 2 hours with about 70 multiple-choice questions (five choices each – a,b,c,d,e). ETS says: “These changes are intended to bring greater accessibility, convenience and options to students around the world who want to stand out and show admissions committees they’re serious about and ready to attend competitive graduate programs.”

Thus, whether or not there is a strong correlation between the physics GRE and graduate school performance, various schools continue to rely on it, in which case. as we saod. we want to offer our assistance. Our flashcards are an attempt to help prepare people for the physics GRE and give them the background information they need. Since we are getting ready to tell you how to work with our set of flashcards (for free!), we should say we have tried very hard to eliminate errors BUT there surely remain things that need to be improved. Please let us know if and when you find any glitches.

By the way, guessing in the pGRE has no longer penalized for some time now so that your final score is simply found from the number of correct answers without any correction made from wrong answers. Thus you will always benefit from guessing. It still will help your guess if you do it smartly – like ruling out obviously wrong answers.

We have well over 250 cards with questions on one side and answers on the other. We carefully studied six of the earlier physics GRE exams and the most recent shortened exam made available for general study by the Princeton Review, plus a GRE sampler (a total of 701 problems) and developed cards to provide the necessary background for all those test questions.

We confess that a (very) few cards are more detailed and complex than might be necessary. The desire to make more complete and more general statements from time to time has been impossible to ignore. In this way, the flashcards may be useful for more than just GRE study. We know graduate students who find it very useful to know this stuff, even for a written PhD qualifier examination. You often need to know the simple introductory limit of a physical model you’re investigating.

To repeat ourselves, the important point we want to make about these cards is that the test-taker must remember many definitions, formulas, and phenomena. If she does not remember, for example, what the Zeeman effect is, she can only guess at a problem involving that effect. As another example, she should not take time to derive the two-slit interference formula, d sin θ = n λ for the maxima. She should just know it by heart, helped by visualizing the path difference that led to the formula! Indeed, there are only 1.7 minutes per problem for the 2 hour and 50 minute exam.

The subject list and approximate percentage of problems devoted to each subject according to the GRE Educational Testing Service (as of 2023 – but with little change from earlier):

Classical mechanics = 20%
Electromagnetism = 18%
Quantum mechanics = 13%
Atomic Physics = 10%
Thermodynamics and statistical mechanics = 10%
Optics and wave phenomena (most waves, very little ray/geometric optics) = 8%
Special relativity = 6%
Laboratory methods = 6%
Specialized topics (nuclear and particle physics, condensed matter physics, astrophysics, mathematical methods, computer applications) = 9%

Mostly correlated with this (but see below), the numbers of cards for a little more detailed list of subjects in our set of cards are as follows:

Classical mechanics = 33 cards
Electromagnetism = 29 cards
Quantum mechanics and atomic physics = 40 cards
Thermal physics = 23 cards
Relativity = 12 cards
Oscillations = 14 cards
Wave optics = 14 cards
Ray optics = 27 cards
Laboratory and electronics = 19 cards
Condensed matter physics = 14 cards
Nuclear and particle physics = 26 cards
Mathematics and statistics = 20 cards
Cosmology = 10 cards
Fluid physics = 3 cards
plus two advice cards on useful tactics for taking the test

It is seen that topics with smaller probability of appearing in the exam still have a large number of cards (especially ray optics and the subjects listed after it). This is largely due to our attempt to help the students study material to which they in fact may not even have much exposure at this time in their coursework. The cards are labeled by subject, and numbered within each subject. (e.g., the 23 Thermal Physics flashcards are labeled 1-TH to 23-TH).

In addition we’d like to use a few extra cards to tell students about the wonderful world of physics here (they illustrate some relevant CWRU facts).

Student Testimonials  (2020-2010 bookend examples)

The GRE flash cards were a wonderful study tool for me.  I found them especially helpful in concert with Prof. Brown’s strategy to review them in 20-30 card installments right before re-working 10 problems at a time from the practice exams (as review after taking the practice exam).  I also found the cards helpful as a quick review right before taking each practice exam under test conditions.  The flashcards are categorized to make the ones I had most trouble remembering easy to find — and their order even became something of a memory tool.  I went from a middling score in my first practice exam, to being quite happy with my score on the actual pGRE. The flashcards, and Prof. Brown’s approach to studying played a key role in my success.

— JRC (Joshua Chiel MS-BS 2020)



“The GRE flashcards were immensely helpful to me. After taking one practice test and looking over the flashcards, I could immediately tell what subjects I needed to study most. The flashcards are organized by subject, so it was easy to find the flashcards that would help me most. I studied the flashcards between practice exams, and I saw my raw score improve by 20 points in a very short amount of time! I was incredibly happy with my actual GRE physics score, and I know that the flashcards contributed immensely to my success.”

— GKK (Gareth Kafka BS 2010)


Get the flashcards 

To get a free electronic set of our flashcards, either a web app or an Android smartphone app, please fill out this online form and we will email you the link.

If we know your email address, we may follow up with updates and corrections (and, we confess, we hope to see if students who apply to our graduate school have also looked at these cards). New (few) corrections are being made from time to time including adding or consolidating a card once in a while.

Best of luck on the physics GRE if you’re taking it, and, really, best luck in everything. (And remember to let us know if you find any card that seems to have an error or some deficiency in it!)

Doc Brown (
CWRU Physics Department