Diagnostic Physics GRE. Suggestions please.

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blueeverest
Posts: 38
Joined: Fri Mar 28, 2008 3:09 pm

Diagnostic Physics GRE. Suggestions please.

Postby blueeverest » Thu Jul 24, 2008 10:38 am

Hi all,

I took the diagnostic Physics GRE test yesterday after a month of preparation. Okay, it wasn't timed and I was at work. But I ended up with a raw score of 40, only in the 53rd percentile. ekk! More disturbing is the fact that I got more incorrect answers than correct ones..way more incorrect. What should I do? I spend a month preparing for this and clearly, that didn't work.

I found the quantum questions were more difficult than I anticipated. Any suggestion guys??? Should I forget about grad school?

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dlenmn
Posts: 577
Joined: Mon Dec 03, 2007 10:19 pm

Re: Diagnostic Physics GRE. Suggestions please.

Postby dlenmn » Thu Jul 24, 2008 1:02 pm

Which test did you take? The one in this booklet? That's an old test, and the consensus seems to be that is the most like the current test of the tests that have been released.


Here's my advice (it's not like I owned the test, so take this with a grain of salt): You should look at the test, see where you need work (solve the problems you got wrong as well), and then do some studying where you need improvement before taking another old test in a more controlled environment (timed and without distractions... note that these tests are not as much like the current test, but they're still good practice). Rinse, lather, repeat. Did you get so many wrong because you tried to answer every question?

The score you got will already get you in to places. Simply by not answering some questions you'd do better still. Plus, you've got plenty of time left. I wouldn't worry too much.

blueeverest
Posts: 38
Joined: Fri Mar 28, 2008 3:09 pm

Re: Diagnostic Physics GRE. Suggestions please.

Postby blueeverest » Thu Jul 24, 2008 2:13 pm

Ya thats the test I took. I was more disappointed because of the number of questions I answered incorrectly. I got 38 wrong :( I cant believe it.

In any case, thanks dlenmn for the suggestion. I didn't 'memorize' all the equations before I took the test. I thought I 'understood' them. But it seems like one has to memorize a lot of equations to do well on this test. For example, I didn't know the lorentz velocity transformation eqns. and there were about 2-3 questions just on that.

Also, the notation used in P-GRE for quantum problems seems completely different than what I am used to seeing.

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dlenmn
Posts: 577
Joined: Mon Dec 03, 2007 10:19 pm

Re: Diagnostic Physics GRE. Suggestions please.

Postby dlenmn » Thu Jul 24, 2008 2:55 pm

blueeverest wrote:I didn't 'memorize' all the equations before I took the test. I thought I 'understood' them. But it seems like one has to memorize a lot of equations to do well on this test. For example, I didn't know the lorentz velocity transformation eqns. and there were about 2-3 questions just on that.


There certainly are equations that need to be memorized -- some of the special relativity ones are good candidates. People have been known to do ok without memorizing a ton of equations, but I should leave someone who did well to comment on that...

blueeverest wrote:Also, the notation used in P-GRE for quantum problems seems completely different than what I am used to seeing.


Bra Ket notation? (e.g. |1> ) Don't be fooled by the notation, most of those problems are super easy. If you've got questions about the notation, you can post them here and people will help out.

VT
Posts: 314
Joined: Fri Nov 09, 2007 12:30 pm

Re: Diagnostic Physics GRE. Suggestions please.

Postby VT » Thu Jul 24, 2008 8:00 pm

blueeverest, QM is supposed to be the easiest one. Have you not taken the QM class yet? You should definitely try to memorize as many equations as you can. You will not have any extra time to actually 'solve' problems during the exam. You still have two more months to go, so do not worry about it too much. What I would suggest now is to go over that practice test, and look at the questions that you did not answer correctly. Then try to memorize all the equations relevant to those problems and also solve the problems from textbooks that are closely related to those problems. I would do this even for the ones that you answered correctly, but def. spend more time on the ones that you did not get right in the test.

EDIT: like dlemn said " RINSE, LATHER ,REPEAT" :)

blueeverest
Posts: 38
Joined: Fri Mar 28, 2008 3:09 pm

Re: Diagnostic Physics GRE. Suggestions please.

Postby blueeverest » Thu Jul 24, 2008 10:32 pm

VT, I have taken QM but honestly I didn't find the problems easy. Maybe I need to work more on QM. My prof. didn't use a standard textbook for QM. He used some sort of handouts that some prof. at a different school is trying to print as a book. So it was basically an experimentation with our class. Initially I thought we covered all the basics and even some more complicated topics but now I feel he skipped a lot. We skipped a whole topic on Spin, and apparently, that is important. And also, I have no idea what raising and lowering of Q harmonic oscillator means. We never did any of those. So now I have to self-teach myself and find some way out.
Personally I thought C. Mechanics was easy and so was Optics and Atomic Physics.
Thanks all for the suggestion. I will try to improve and come back with good news :)
Cheers.

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dlenmn
Posts: 577
Joined: Mon Dec 03, 2007 10:19 pm

Re: Diagnostic Physics GRE. Suggestions please.

Postby dlenmn » Fri Jul 25, 2008 1:08 am

You didn't find the QM problems easy because you don't know the notation, which is not uncommon since some popular intro QM books (like Griffiths) don't really use it. After a quick skim, I'd say that 28, 29, 45, 83, and 94 (the raising and lowering operator) are really just tests of knowing bra ket notation -- you don't actually need to know what the operators are really for. Because they're given, all you need to do is a little arithmetic. That said, the harmonic oscillator is kind of a big deal, so it's worth some study. Did you work with it, just without the raising and lowering operators?

There are also a couple of QM questions related to electrons in atoms. That stuff probably calls for some memorization (knowing how the electrons go about in the hydrogen atom is also kind of a big deal).

blueeverest
Posts: 38
Joined: Fri Mar 28, 2008 3:09 pm

Re: Diagnostic Physics GRE. Suggestions please.

Postby blueeverest » Fri Jul 25, 2008 9:11 am

You were right. there are too many problems just for QHOs. I tried but I couldnt go pass the notation. As you guys said, i need to familiarize myself with the notation. I think I am fine with electrons in Hydrogenic atoms (atleast for this test).

I have requested "Problems in Quantum Mechanics" by Goldman from my lib. Hopefully that should help me.

Since i go to a small lib arts school, doing well on the PGRE is the only way to get into a good program. So this OCt test really is big for me.




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