## 11/10/2012 PGRE Exam

Newton
Posts: 20
Joined: Tue Nov 06, 2012 6:34 am

### 11/10/2012 PGRE Exam

So I just go back from taking the PGRE in Munich. Long day. Woke up at 4AM, drove an hour to the train station, then took a 2 hour train to Munich...

I didn't think it was too bad. Most of the questions hardly took much thinking if you knew the basics. There were no tedious ones with Maxwell-Boltzmann statistics/Partition Functions or the likes However, I did leave around 15-20 blank. I answered about 70 on the first pass then when back and looked at the ones I skipped and did 50/50 guesses on some, but I ended up running out of time before I could look at the ones in the back of the exam. I distinctly remember telling myself on the first pass I was wasting too much time thinking about tough ones. Some of the ones I skipped were you either knew the factoid or not. O well

P.S. some students didn't even bring No.2 pencils... how dense are these people?!?!

johnhero2010
Posts: 36
Joined: Tue Apr 24, 2012 9:25 am

### Re: 11/10/2012 PGRE Exam

Newton wrote:So I just go back from taking the PGRE in Munich. Long day. Woke up at 4AM, drove an hour to the train station, then took a 2 hour train to Munich...

I didn't think it was too bad. Most of the questions hardly took much thinking if you knew the basics. There were no tedious ones with Maxwell-Boltzmann statistics/Partition Functions or the likes However, I did leave around 15-20 blank. I answered about 70 on the first pass then when back and looked at the ones I skipped and did 50/50 guesses on some, but I ended up running out of time before I could look at the ones in the back of the exam. I distinctly remember telling myself on the first pass I was wasting too much time thinking about tough ones. Some of the ones I skipped were you either knew the factoid or not. O well

P.S. some students didn't even bring No.2 pencils... how dense are these people?!?!
I think it was not easy or hard but the problem is that most of the question are new
it is true that the shape and maybe the phrases are familiar from the official tests but when u try to do them, u find that it is a scam and it is a total different problem with new tricks and u figure it out
anyways iam not that sad though i answered a little no of problems, i guess today's exam was a real test to measure where u r in understanding...... and even measuring how much r u being saturated with Physical Concepts
that is it.....I guess
by the way...I brought 4 (2B pencils) and it didn't help at all
Good luck everyone
Last edited by johnhero2010 on Sat Nov 10, 2012 12:33 pm, edited 2 times in total.

Lavabug
Posts: 66
Joined: Tue Mar 27, 2012 6:19 pm

### Re: 11/10/2012 PGRE Exam

Did it in Canterbury today(only about 6 people doing physics). Tables were small and flimsy, probably the most uncomfortable 3 hours of test taking I've ever had.

It was alright, answered 71, I think I made educated guesses on around 10. I could have done 10-12 more if it weren't for the silly time constraints, but I didn't exactly train myself for speed so I paid the price.

It was very much similar to the latest pgre practice exam, I'd say 3/4 of the questions were very much the same, asked differently. Hope I didn't make careless mistakes.

Edit: ETS site says my status is "absent or not available", this is what shows up for everyone right? I panicked for a bit. Also I noticed that my scores are being sent to the WRONG universities... when I asked them to change it via email twice months ago! The changes even showed up on the page back then after about a week. So infuriating, looks like I'll have to shell out another 25-50$to ETS... Newton Posts: 20 Joined: Tue Nov 06, 2012 6:34 am ### Re: 11/10/2012 PGRE Exam Seems you did exactly what I did on the exam lavabug. I did my practice exams with a little be more cushion on time. Though we had a classroom with nice large tables There were 30 students total, some math and some physics, which was sorta distracting. I agree that most of the questions were testing the same knowledge, on some of my guesses I used that knowledge to guide me. The more I think about the exam the more I am worried that I made some careless mistakes. What did you put for the question that had something like the "expectation value" of the Hamiltonian, with wave-functions n & m and energy states n and m? Last edited by Newton on Sat Nov 10, 2012 1:09 pm, edited 1 time in total. Newton Posts: 20 Joined: Tue Nov 06, 2012 6:34 am ### Re: 11/10/2012 PGRE Exam No worries lavabug. I just checked ETS and I have the same phrase listed. I already have to shell out 25-75$ because I need to apply to more safety schools

esopterodactyl
Posts: 22
Joined: Tue Jan 31, 2012 3:54 pm

### Re: 11/10/2012 PGRE Exam

Ha. I was also in Canterbury for that joke of a "test center". Surely the ETS could find a more reputable university to administer these tests...
The exam itself was straight forward, much easier than the MIT prep tests.

Newton
Posts: 20
Joined: Tue Nov 06, 2012 6:34 am

### Re: 11/10/2012 PGRE Exam

What do you mean MIT prep tests? Are you talking about the OpenCourse stuff? I saw those lectures on YouTube but I went with the Yale lectures instead... IMO they seemed better. It was a good refresher course for me, since I haven't studied any of this stuff in 5 years.

esopterodactyl
Posts: 22
Joined: Tue Jan 31, 2012 3:54 pm

### Re: 11/10/2012 PGRE Exam

Sorry about that, I meant this:
http://www.physicsgreprep.com
It was started a year or so ago (and posted on this site)

hooverbm
Posts: 19
Joined: Tue Aug 28, 2012 7:32 pm

### Re: 11/10/2012 PGRE Exam

After much preparation, felt the test was easy concept/problem wise. Difficulty came from time constraints. Some either know it or you don'ts type questions, which I'm not a fan of.

Some cheap trick questions, which I thankfully didn't get wrong after looking up the answers when I got home. But BS 50/50s where the answer was different by a positive or negative. Stupid. Wasted time I could have spent somewhere else.

Some problems that took easy concepts and made them tedious by pointless calculations. Skipped a few of those for time's sake.

Skipped about 12 problems, but heavily invested that time well for the other ones. Fairly confident, after looking up uncertain problems later, in about 80 problems or so. We'll see what happens.

Lavabug
Posts: 66
Joined: Tue Mar 27, 2012 6:19 pm

### Re: 11/10/2012 PGRE Exam

Newton wrote: What did you put for the question that had something like the "expectation value" of the Hamiltonian, with wave-functions n & m and energy states n and m?
There was only 1 that made sense, the one with the Kronecker delta.

God I was really hoping not to give into the temptation of checking my answers... but the one on distances in NaCl... I think it was a trick question, I hope 2r was the correct distance between contiguous Na+ ions given that r was the distance between Na+ Cl-. They probably mentioned FCC structure to distract...

I really rushed through a lot of them barely reading the question, just looking for keywords. Kinda had doubts about the spherical harmonic question, I'm not sure if I read it correctly but if it was for m=0, then it was ccostheta. I hope the question didn't say l=0... I never remembered these things, on my quantum mechanics exam we would be given Clebsh-Gordan tables because knowing equations were the least of our worries.

Pretty embarrassed for not figuring out the telescope problem quickly, considering I'm applying to astronomy programs mainly.

hooverbm
Posts: 19
Joined: Tue Aug 28, 2012 7:32 pm

### Re: 11/10/2012 PGRE Exam

Looks like we had some different problems.

Thankfully I didn't have too many optics problems. I think the exam says 9% or something? The problem is that I find the subject material so boring, that I have an issue sitting down and digesting it. I skipped 1 optics problem. Pretty sure I knew the answer, but it got lost in the hustle of answering other skipped problems.

You would never need a Clebsh-Gordan table on an exam like this. The problems with total orbital angular momentum will always be a quick trick, like the practice exam problems.

I'm surprised that I got all the Quantum questions right. Some weird qualitative questions that I never thought about before, but ended up getting correct in the end. Quantum on this exam is definitely at the bare minimum level.

lanza
Posts: 3
Joined: Mon Nov 05, 2012 5:55 pm

### Re: 11/10/2012 PGRE Exam

They need new test makers. Far too many problems where you could understand the physics thoroughly but misplace a 2 or a sqrt(constant) somewhere. I feel like this much emphasis on basic arithmetic completely eschews the physics behind it all.

Meteorshower
Posts: 26
Joined: Sat Sep 01, 2012 4:29 pm

### Re: 11/10/2012 PGRE Exam

Also sat it in Canterbury! Was lucky enough to get one of those tables where the computers were at. Much more room. Thought the test was fairly easy. I was pretty much the only person with no view of the clock, so I rushed it and had finished my first pass and was slightly through my second when the guy was like "1 hour left" and I almost burst out laughing.

TOTALLY not amused that the only test centre in the country is in Canterbury though. Especially when you live in Scotland...

Izaac
Posts: 63
Joined: Tue Mar 20, 2012 2:24 am

### Re: 11/10/2012 PGRE Exam

Here's my debrief from Chicago.

First thing, I exploded of laugh when opening the exam when I realized that there was a good dozen of questions IDENTICAL to the october test I took (purely, stupidly i-den-ti-cal). For future generations, I strongly advise to take the two tests (Oct. and Nov.).

I might have answered a good 90+ questions, didn't double check though, and was rather ambitious on the guessing (but always reduced to two choices). But am rather confident on a good (?) score.

Now, QUESTION! I had this question about a particle having momentum mc; the question was, what is the kinetic energy?
Among the answers, there was some variations of the traditional $$\frac{1}{2}mv^2$$, but I decided on the last one, the infinity. I mean, a non-zero mass particle going at speed of light is by definition impossible, so an impossible energy seemed the only senseful answer to me...
What do you think about it?

King Vitamin
Posts: 42
Joined: Sat Nov 12, 2011 5:01 pm

### Re: 11/10/2012 PGRE Exam

Izaac wrote: Now, QUESTION! I had this question about a particle having momentum mc; the question was, what is the kinetic energy?
Among the answers, there was some variations of the traditional $$\frac{1}{2}mv^2$$, but I decided on the last one, the infinity. I mean, a non-zero mass particle going at speed of light is by definition impossible, so an impossible energy seemed the only senseful answer to me...
What do you think about it?
I didn't take the test, but if I'm understanding the question correctly (particle has momentum mc, what is kinetic energy E - mc^2), seems like kinetic energy should be (Sqrt[2]-1)*mc^2.

Newton
Posts: 20
Joined: Tue Nov 06, 2012 6:34 am

### Re: 11/10/2012 PGRE Exam

I had planned to take the PGRE in October but I didn't sign up soon enough and I would NOT have been ready I don't think. Two weeks is not enough.

Yeah, I took too much time on the NaCl question and I didn't know exactly the approach so I didn't guess. I don't remember the the kinectic energy problem but what about the percent error in the measurement of the kinetic energy when you know velocity within 10%?? I was sort of unsure about that one?!

Lavabug
Posts: 66
Joined: Tue Mar 27, 2012 6:19 pm

### Re: 11/10/2012 PGRE Exam

Newton wrote:I had planned to take the PGRE in October but I didn't sign up soon enough and I would NOT have been ready I don't think. Two weeks is not enough.

Yeah, I took too much time on the NaCl question and I didn't know exactly the approach so I didn't guess. I don't remember the the kinectic energy problem but what about the percent error in the measurement of the kinetic energy when you know velocity within 10%?? I was sort of unsure about that one?!
Yeah this one was different from the error problem in the 2010 sample. The relative error for an observable x goes like error/x, but if some other magnitude(ie: KE) depends on it like x^n, the error would be n*error/x, so the correct answer was 20%. (you take the absolute values of the ln() of whatever expression depends on a parameter(s) with known uncertainties, then differentiate).

I got kind of stumped on the relativistic KE question, would've taken me too long to figure it out.

Looks like everyone keeps getting consistently better at the pgre. I'm starting to think I might be below the 50th percentile now...

Newton
Posts: 20
Joined: Tue Nov 06, 2012 6:34 am

### Re: 11/10/2012 PGRE Exam

Damn. I kept thinking to myself the old uncertainty equation we learn in our physics lab and I couldn't make sense of it. So I ended up putting 10%. Freaking careless mistakes are gonna hurt I'm not shooting anywhere great so I just would like ~700.

hooverbm
Posts: 19
Joined: Tue Aug 28, 2012 7:32 pm

### Re: 11/10/2012 PGRE Exam

Damn. I wish I had taken an October test. I looked for an opening on the website around September, but couldn't find a date for October for some reason.

If I were to give advice to future test takers, focus pretty much entirely on the 2008 exam. It feels like all the questions were VERY similar or asked in different ways to questions on the 2008 exam. Same topics are covered from the 2008 exam in similar ways. The 2008 exam was matrix question heavy. The current exam also covers more matrix questions (not found in earlier exams). I also found that if a topic isn't covered on the 2008 exam, guess what? It's not on the current test, so you don't have to bother with learning it.

I spent a lot of time reviewing supplementary material, but you could study for 2 months comfortably and earn a perfect score.

As for the kinetic energy question, I'm not sure I had a question like that. But if it's non-relativistic you're given a momentum. Kinetic energy is p^(2)/2m. Otherwise, use a relativistic form. Not sure if they're talking about a photon or not. It sounds like this is a particle with mass.

mhrazeghi58
Posts: 38
Joined: Mon Sep 03, 2012 6:28 pm

### Re: 11/10/2012 PGRE Exam

Hi guys. How many true answer we should have to earn score 990 in 10 November pgre? I mean in comparison with 2008 test sample. What's your guess?

hooverbm
Posts: 19
Joined: Tue Aug 28, 2012 7:32 pm

### Re: 11/10/2012 PGRE Exam

The current exam looks to be about the same difficulty as the 2008 exam. I would expect the scoring to be very similar.

dau
Posts: 19
Joined: Thu Nov 01, 2012 10:36 am

### Re: 11/10/2012 PGRE Exam

hooverbm wrote:The current exam looks to be about the same difficulty as the 2008 exam. I would expect the scoring to be very similar.
I agree with the difficulty level. Also, I think the 2008 test is the only one representative of the current test. In my opinion, as hooverbm said before, one should specially focus on this exam for PGRE preparation.

mhrazeghi58
Posts: 38
Joined: Mon Sep 03, 2012 6:28 pm

### Re: 11/10/2012 PGRE Exam

Sorry can I ask what do you mean when you say 2008 exam? I have a sample test that is a test collection ( I guess) from 2007 to 2010 PGRE exams.

hooverbm
Posts: 19
Joined: Tue Aug 28, 2012 7:32 pm

### Re: 11/10/2012 PGRE Exam

That's the 2008 exam.

The 86 and 92 exams are useful prep to time yourself. I would probably ignore the 96 exam. It is so grossly misrepresentative of the type of questions you see on the new exam, that you shouldn't even bother with it.

What I would do if I could do it again is to really study the 2008 exam. Do the 86 and 92 for timed purposes. Look at each question on the 2008 closely. If you see thin films, go back through older exams to see the variety of questions asked about that topic. Do some further supplementary review. Repeat for each question on the 2008.

That's pretty much all you need to do. Instead of doing a broad and general review (like I did), you want to do a more focused one where the 2008 exam is your primary source.

Newton
Posts: 20
Joined: Tue Nov 06, 2012 6:34 am

### Re: 11/10/2012 PGRE Exam

Yeah. I would agree with the previous statement. I took each of the five practice exams, starting with the 2008 exam working backwards. I figured out which ones I missed and studied up on those subjects and memorized the factoids (didn't help) then two days before the exam I retook the 2008 exam and reviewed all the standard equations and problems. This helped a lot. I was blazing through the exam on the 10th but I got hung up on some problems and I wasted too much time.

Any future takers should just study the 2008 exam intensely and work on time management. That is the key.

blighter
Posts: 256
Joined: Thu Jan 26, 2012 6:30 pm

### Re: 11/10/2012 PGRE Exam

I took the test in Delhi. The centre was quite nice and comfortable. Nothing to complain about. I'm expecting around 800. But the test was much easier than the practice test. So I'm afraid I might get a lower score. That, combined with my ridiculously low GPA and zero research experience, it's safe to say I'm doomed. I don't intend to apply to top schools. Even the lowest ranked ones would reject me. Fortunately I have one more year to go. I might retake it.

I never did the complete practice test. Didn't have the time. I sat for an hour on the 2008 test hoping to go through at least 33 questions. That way I could scale it to 100 questions in three hours. But I could barely finish 20. So I was very scared. But the exam went better than expected and I was able to answer more questions than I'd hoped. That's what makes me suspect the test was easier.

Newton
Posts: 20
Joined: Tue Nov 06, 2012 6:34 am

### Re: 11/10/2012 PGRE Exam

I was surprised by the lack of problems where you have to consider taking the variable to their limits. There were a lot of those types of problems on the practice exams. But I only saw on this one, had to do with the particle move in the spherical shell. I looked at the number and if I didn't miss any questions (doubtful), I will get a 950. But if I miss 24 questions I'll get a 750ish. I'm going off the old 2008 breakdown considering the exams where pretty similar.

esopterodactyl
Posts: 22
Joined: Tue Jan 31, 2012 3:54 pm

### Re: 11/10/2012 PGRE Exam

During the test, I actually thought the same exact thing about 'limiting cases'. I considered redoing problems with that in mind, but obviously didn't have time for that.
As someone who's taken this beast of a test before, lower your expectations. Unless you are really confident in your answers (and can remember getting 95-100% absolutely correct), expect to get some wrong.
I felt good after my exam last year and got a 700 - I just left way too many blank. If you got 20+ wrong on the practice tests, that's probably what you'll end up with on the real thing...

Newton
Posts: 20
Joined: Tue Nov 06, 2012 6:34 am

### Re: 11/10/2012 PGRE Exam

I am most def. preparing myself for a lower score. But I didn't really guess much which I was doing on my practice exams. If it wasn't 50/50, I skipped it. I would be happy with a 700 at this point. I have GPA factors which already limit my choices. So I just need to beat the cutoff for mid-tier Off to write my SOP.

tamaghna
Posts: 14
Joined: Thu Aug 15, 2013 4:27 pm

### Re: 11/10/2012 PGRE Exam

Lavabug wrote:
Also I noticed that my scores are being sent to the WRONG universities... when I asked them to change it via email twice months ago! The changes even showed up on the page back then after about a week. So infuriating, looks like I'll have to shell out another 25-50\$ to ETS...
Did it stay that way right till the end? Because I gave the exam a couple of days back now and its the same with me: the wrong univs are shown even though i had emailed them my preferences in time. Did you have to do anything to get it corrected?

Cheers,
Tamaghna

tamaghna
Posts: 14
Joined: Thu Aug 15, 2013 4:27 pm

### Re: 11/10/2012 PGRE Exam

Lavabug wrote:
Newton wrote: What did you put for the question that had something like the "expectation value" of the Hamiltonian, with wave-functions n & m and energy states n and m?
There was only 1 that made sense, the one with the Kronecker delta.

God I was really hoping not to give into the temptation of checking my answers... but the one on distances in NaCl... I think it was a trick question, I hope 2r was the correct distance between contiguous Na+ ions given that r was the distance between Na+ Cl-. They probably mentioned FCC structure to distract...

I really rushed through a lot of them barely reading the question, just looking for keywords. Kinda had doubts about the spherical harmonic question, I'm not sure if I read it correctly but if it was for m=0, then it was ccostheta. I hope the question didn't say l=0... I never remembered these things, on my quantum mechanics exam we would be given Clebsh-Gordan tables because knowing equations were the least of our worries.

Pretty embarrassed for not figuring out the telescope problem quickly, considering I'm applying to astronomy programs mainly.
I had my Physics GRE this Saturday and i think i got the exact same paper that you did back then. I agree with you on the first point. But i thought sqrt(2)r is the right answer for the NaCl problem, since the nearest Na atom looks like its on the diagonal (up once and left/right once to reach another Na atom). I dont remember the third one exactly, but if it had n=2 then i went for the one with the (1-e^r/a0) factor since there needs to be a radial node. Do you remember what th question asked for?