Harvard-Radcliffe Society of Physics Students

Those of us who plan to go on to graduate school in physics will almost surely have to take
the physics GRE. This test is brought to us by the fine folks at
ETS, who are also responsible for the SAT's.

Basic Test Information

The physics GRE is like an SAT II on steroids. You're given 170 minutes to answer 100
multiple-choice questions. No resources are allowed, although the front page of the test does
list a fair number of helpful constants and a few moment of inertia equations. It's a
difficult test: usually, getting about 80% of the questions right is good enough to get a perfect score of 990.
(Why is the test scored out of 990? Only ETS knows for sure.)

The annoying thing about the GRE is that while a bad GRE score will definitely hurt your
chances in graduate school admissision, a good score won't really help you that much.
However, the test is difficult enough so that it's really worthwhile to spend some time
preparing for the test to maximize your chances of doing well.

Registering for the Test

If you're planning on taking the physics GRE, it's important to register for the test early.
You can register online any time through the GRE registration page.
(Warning: this particular link may change, but it should always be easy to figure out how to
register from the main GRE site.) Registration costs around $130 at the moment.

Unlike the general GRE's, the physics GRE (and other subject GRE's) are given about once a
month. This means that the test centers for each testing session fill up fairly quickly. When
you sign up for the test, ETS will ask you to name your two preferred test centers. ETS will
"try" to assign you to one of them, but as often as not you'll get something entirely different.
People have been assigned to test centers in a different state before. Anyway, the test centers
most convenient to Harvard are probably Suffolk, Simmons, or Roxbury Community College.

If you get assigned a crappy test center (Salem, Fitchburg, Providence), you can call ETS
to change where you take it. Sometimes they charge you to change the location, sometimes not.
(If you're getting the impression that ETS are a bunch of disorganized buffoons, that's
because they are!)

Once you're registered for the test, ETS will mail you a little packet that contains a booklet
with a practice test and your admissions ticket. Hopefully. Sometimes the ticket comes separately
and later. If it's ten days before the test and you still haven't gotten the ticket, call
ETS up and try and get them to mail it again, after verifying the address they have on file for you.
The only piece of information you really need is your "registration number"; if you have that
and appropriate identification, you shouldn't need your admissions ticket. (At least that's
what the woman on the phone just told me. I hope it's true...)

Studying for the Test

The basic thing to know about the physics GRE is that it covers a fairly wide range of
topics very superficially. A lot of the test relies on knowing a bunch of random formulae
and how to do certain stock problems. Most of the material covered in Harvard physics classes
is much more complicated and open-ended than what the GRE asks of you. The best basic
approach to studying is probably to review your notes from 15a/16, 15b, and 15c.

You should probably try to form a study group for the GRE. Email physics@hcs about this
if SPS isn't already organizing a group. Talking about problems with other people is
probably not as helpful as just studying formulas intently on your own, but no one wants
to study for any of this, and being in a study group will force you to at least start
thinking about things more than a few days before the test.

Here is the breakdown of the subjects covered in the physics GRE, copied verbatim from
ETS's booklet. They're sorted by what percentage of the test is devoted to the topic.

• Classical Mechanics (20%) Kinematics, Newton's laws, work and energy, rotational motion about a fixed axis, dynamics of a system of particles, central forces and celestial mechanics, three-dimensional particle dynamics, Lagrangian and Hamiltonian formalism, noninertial reference frames, elementary topics in fluid dynamics.
• Electromagnetism (18%) Electrostatics, currents and DC circuits, magnetic fields in free space, Lorentz force, induction, Maxwell's equations and their applications, electromagnetic waves, AC circuits, magnetic and electric fields in matter.
• Quantum Mechanics (12%) Fundamental concepts, solution of the Schrodinger equation (including square wells, harmonic oscillators, and hydrogenic atoms), spin, angular momentum, wave function symmetry, elementary perturbation theory.
• Thermodynamics and Statistical Mechanics (10%) Laws of thermodynamics, themodynamic processes, equations of state, ideal gases, kinetic theory, ensembles, statistical concepts and calculation of thermodynamic quantities, thermal expansion and heat transfer.
• Atomic Physics (10%) Properties of electrons, Bohr model, energy quantization, atomic structure, atomic spectra, selection rules, blackbody radiation, x-rays, atomis in electric and magnetic fields.
• Optics and Wave Phenomena (9%) Wave properties, superposition, interference, difraction, geometrical optics, polarization, Doppler effect..
• Specialized Topics (9%)
  • Nuclear and Particle Physics. Nuclear properties, radioactive decay, fission and fusion, reactions, fundamental properties of elementary particles
  • Condensed Matter. Crystal structure, x-ray diffraction, thermal properties, electron theory of metals, semiconductors, superconductors
  • Miscellaneous. Astrophysics, mathematical methods, computer applications
• Special Relativity (6%) Introductory concepts, time dilation, length contraction, simultaneity, energy and momentum, four-vectors and Lorentz transformation, velocity addition.
• Laboratory Methods (6%) Data and error analysis, electronics, instrumentation, radiation detection, counting statistics, interaction of charged particles with matter, lasers and optical interferometers, dimensional analysis, fundamental applications of probability and statistics.

Study Books

At the time of writing -- November 2005 -- the rule seems to be this: all the published study books suck. They do have practice tests, though, which might be useful; but I'm told that these tests are really hard and not in the style of the current GRE. So you probably don't want to bother with these. (Particular revile has been displayed towards "the purple book", whichever one that happens to be.)

SPS Notes

Some gracious SPS members have put together study sheets for various topics. We hope you find them useful.
If you're studying for the GRE and put something similar together, please send it along to physics@hcs for
inclusion on this site.

• General notes by Steve Byrnes (11/2005) (LaTeX source)
• Two-day Guide to taking the Physics GRE.pdf by Lin Cong (11/2008)
• Classical Mechanics notes by Susannah Dickerson (11/2005)
• General Equations for the Physics AP, origin unknown
• Lab Methods notes by Michelle Borkin (11/2005)
• Lab Methods+Review typed in word by Shan (07/2008)
• Quantum Mechanics notes by Peter Williams (10/2005) (LaTeX source)
• Thermodynamics notes by Susannah Dickerson (11/2005)
• Thermodynamics Thermodynamics notes typed up in word by Shan (07/2008)
• Special Relativity notes by Bryan Chen
• Doug McClure put together atomic physics notes, but I only have a hard copy

If anyone wants to be a superhero, it would be awesome to take some of these scanned-in notes and write
them up as LaTeX files. That way the files are a lot smaller, and we can improve the notes over time.
Email physics@hcs if you are cool enough to accept this mission.

Practice Tests

• 8677 practice test
• 9277 practice test
• 9677 practice test

Other Resources

There's a lot of info on the GRE online. Google is your friend. Links of particular interest:

• Detailed solutions to some common GRE practice tests (including the ones above)
• PhysicsGRE.com is a nice, thorough noncommercial site.
• Fill in more here ...

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