Physics GRE test today

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somebody
Posts: 68
Joined: Tue Jun 13, 2006 4:25 pm

Physics GRE test today

Postby somebody » Sat Dec 02, 2006 4:52 pm

anybody else think that test was pretty easy? i think i could have answered 80-85 questions if i had time, i kept making dumb algebra and computational mistakes though so my score might not be as good. stupid time limit

nb
Posts: 38
Joined: Sat Dec 02, 2006 5:16 pm

?

Postby nb » Sat Dec 02, 2006 5:19 pm

...?
Last edited by nb on Sat Mar 03, 2007 11:59 am, edited 1 time in total.

eyalb
Posts: 1
Joined: Sat Dec 02, 2006 5:19 pm

today test

Postby eyalb » Sat Dec 02, 2006 5:27 pm

Hey ,

I think its a good idea!
can u remember some of the questions and ur answers?

somebody
Posts: 68
Joined: Tue Jun 13, 2006 4:25 pm

Postby somebody » Sat Dec 02, 2006 5:28 pm

there were a 5 or 6 questions on sound that I had absolutley no clue on, we never covered that at my school and i had no inclination to study

nb
Posts: 38
Joined: Sat Dec 02, 2006 5:16 pm

Postby nb » Sat Dec 02, 2006 5:33 pm

yes it was realy strange I skiped that questions, I cant remeber the questions..it will be intersting to see if we can solve it now that we are more relaxed

Wanna Be Physicist
Posts: 27
Joined: Thu Dec 29, 2005 8:56 pm

hmm

Postby Wanna Be Physicist » Sat Dec 02, 2006 9:06 pm

I felt that test was harder than the one in November. It will be interesting to see my results. This was the consensus I got from others in the room who also took the test last month.

Many of the questions didn't lend themselves to quick calculation as before.

jgentleman
Posts: 3
Joined: Sat Dec 02, 2006 9:10 pm

Postby jgentleman » Sat Dec 02, 2006 9:17 pm

I agree with the last poster that the calculations on this test were quite cumbersome. Based on the green physics practice test booklet I got sent in the mail (GR0177), I expected the algebra to be simpler.

Overall, the test to me was not hard theory-wise. What made it hard was the never-ending barage of burdensome calculations. Not my idea of a good time.

I would recommend for anyone taking this test to practice doing a lot of problems without a calculator. Oh, and memorize as many formulas as you can so you don't have to spend crucial time deriving stuff.

somebody
Posts: 68
Joined: Tue Jun 13, 2006 4:25 pm

Postby somebody » Sat Dec 02, 2006 9:42 pm

i didnt take the november test, but when i said I thought this test was easy i was referring more to the theory. there weren't many problems I looked at and said "I dont know how to do this" but there were a bunch I looked at and said "I dont have time to work this out." Off the top of my head I remember the one you had to find the Lagrangian of the bowl and the one where you had to find the Hamiltonian of the atwood's machine as ones I skipped because it would have taken me a few minutes to reason through to get the answer. Also, to anybody taking the test in the future, memorize the sines and cosines of key angles! I must have written the 30-60-90 triangle six or seven times during the course of the test.

Pchemist
Posts: 13
Joined: Thu Dec 08, 2005 8:17 pm

how many queston did you answer

Postby Pchemist » Sat Dec 02, 2006 11:21 pm

I answer like 75.

astrobio
Posts: 27
Joined: Sat Dec 02, 2006 11:37 pm

Postby astrobio » Sat Dec 02, 2006 11:47 pm

In general, I actually thought the content of the test was really easy.

That being said, I answered 57, and based on my performance on the practice tests, I probably got up to 40% of those wrong. I haven't taken a physics class in 2.5 years, so all I'm hoping for is in the 600ish range, which hopefully I managed. I just about killed myself because there were at least 4 questions that I glanced at the formulas for on flash cards yesterday, said:

"Oh, these haven't been on any of the practice tests."

*TOSS*

Yup. Worked out real well.

I was also surprised by the number of astronomy related questions on the test. It seemed much higher than on any of the ETS practice tests.

somebody
Posts: 68
Joined: Tue Jun 13, 2006 4:25 pm

Postby somebody » Sat Dec 02, 2006 11:49 pm

i think i answered about 65-75 which i didn't think was that bad (I was only aiming for 650 - 700 score though), I'd like to shake the hand of anybody who managed to grunge through all those calculations and finish every problem.

nb
Posts: 38
Joined: Sat Dec 02, 2006 5:16 pm

Postby nb » Sun Dec 03, 2006 3:06 am

anyone remembers some of the questions ?

nb
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Joined: Sat Dec 02, 2006 5:16 pm

Postby nb » Sun Dec 03, 2006 3:12 am

someone solved the Hamiltonian of the atwood's machine or the Lagrangian of the bowl ?

pascal
Posts: 7
Joined: Sat Dec 02, 2006 5:19 pm

Atwood machine

Postby pascal » Sun Dec 03, 2006 3:31 am

I can't recite the complete Lagrangian, but I know that there was only choice with a relative minus sign between m_1 and m_2 in the "-V" portion of the Lagrangian, and that was the right choice. I actually got really lucky, because believe it or not, we covered that exact problem in one of my classes just last week! Even then it still took me probably five minutes to figure it out...

Wanna Be Physicist
Posts: 27
Joined: Thu Dec 29, 2005 8:56 pm

Prism

Postby Wanna Be Physicist » Sun Dec 03, 2006 3:45 am

"An ray is incident upon a equilateral prism and the refracted ray is parallel to one of the sides of the prism, find the angle of incidence"

or the

"which one of these elements is least likely to be produced during thermonuclear fusion within the sun" WTF? I never took that class.

Oh well, I'm going to get drunk now.

I miss the good ole E&M questions, they certainly didn't seem like they were 20% of the test.

somebody
Posts: 68
Joined: Tue Jun 13, 2006 4:25 pm

Postby somebody » Sun Dec 03, 2006 3:47 am

the toughest thing for me was writing that honor statement in cursive before the test because I haven't written in cursive since the 5th grade

aufuk
Posts: 7
Joined: Sun Dec 03, 2006 4:07 am

Postby aufuk » Sun Dec 03, 2006 4:17 am

Hi,
I think the answer of the question about fusion in the sun is silicon, since there is very little amount of silicon in the sun.
The angle of the ray between prism is 49.

And does anybody have any idea about ionization energy of helium? I answered as 25.2 eV

somebody
Posts: 68
Joined: Tue Jun 13, 2006 4:25 pm

Postby somebody » Sun Dec 03, 2006 4:36 am

i dont remember the question that well but i remember thinking that since there was no inter-electron action, the electrons would behave like they were in a columb potential with Z = 2, i think i used the bohr formula or something

nb
Posts: 38
Joined: Sat Dec 02, 2006 5:16 pm

Postby nb » Sun Dec 03, 2006 4:40 am

you right about the helium...25

How did you solve the optic problem ?

nb
Posts: 38
Joined: Sat Dec 02, 2006 5:16 pm

Postby nb » Sun Dec 03, 2006 5:44 am

anyone remember the paraboloid-magnetic flux question ?

aufuk
Posts: 7
Joined: Sun Dec 03, 2006 4:07 am

Postby aufuk » Sun Dec 03, 2006 5:48 am

snell reflection law. you then can find the answer 49 by elimination,since the sinus of the angle that you want to find a little bigger than sinus of 45.

aufuk
Posts: 7
Joined: Sun Dec 03, 2006 4:07 am

Postby aufuk » Sun Dec 03, 2006 5:50 am

I am not sure about paraboloid but i thought that the total magnetic flux should be zero so the answer is minus phi

nb
Posts: 38
Joined: Sat Dec 02, 2006 5:16 pm

Postby nb » Sun Dec 03, 2006 6:19 am

Nice aufuk...do you remember more questions

pascal
Posts: 7
Joined: Sat Dec 02, 2006 5:19 pm

Helium/Resistors

Postby pascal » Sun Dec 03, 2006 10:10 am

nb--are you sure about the helium being 25? I figured you'd take Z^2(13.6)=54.4 eV. Also, does anyone remember the problem with the five resistors? (It was within the first ten questions) I couldn't figure out what to do with that middle resistor! I think it asked for the current through one of the first resistors...

astrobio
Posts: 27
Joined: Sat Dec 02, 2006 11:37 pm

Fused Elements

Postby astrobio » Sun Dec 03, 2006 11:35 am

I figured elements in the sun that the sun can produce by fusion would be more relatively abundant-- so things up to Fe. Anything over Fe is typically produced in supernova explosions, so I figured they would be less likely to show up in the sun.

aufuk
Posts: 7
Joined: Sun Dec 03, 2006 4:07 am

Postby aufuk » Sun Dec 03, 2006 2:28 pm

Pascal, the formula( Z^2/n)13.6 is valid for hydrogenlike atoms.so you cannot apply it to helium.55 is the ionization energy of helium (+) ion, which is hydrogenlike. But i am not sure about the question. Was the question ionization energy of helium or something else? anyone remember?

Pchemist
Posts: 13
Joined: Thu Dec 08, 2005 8:17 pm

helim problem

Postby Pchemist » Sun Dec 03, 2006 3:23 pm

I think they specifically asked us to ignore electron-electron repulsion. so each electrion will see a +2 charge from nucleus, in order word, the nucleus is "unshielded" so it's like (2)^2*13.6eV per electron, and it's 2*54eV

108eV.

I used Z instead of Z^2

Pchemist
Posts: 13
Joined: Thu Dec 08, 2005 8:17 pm

Postby Pchemist » Sun Dec 03, 2006 3:24 pm

dipole radiation.

hey guy, do you know if the dipole radiation problem, is it maximum between theta=Pi/2 and theta=-Pi/2?

graviton
Posts: 10
Joined: Sun Dec 03, 2006 3:03 pm

Postby graviton » Sun Dec 03, 2006 3:36 pm

I really would like to know how people who took the november test (or any previous test) would rate this one in difficulty since the scores are scaled accordingly.

pascal
Posts: 7
Joined: Sat Dec 02, 2006 5:19 pm

dipole radiation

Postby pascal » Sun Dec 03, 2006 3:37 pm

Thanks, Aufuk. I don't remember the dipole radiation problem exactly, but I do know EM radiation is a maximum at an angle of 90 degrees from the axis of acceleration of the particle (i.e., if a particle is oscillating along the x-axis, the maximum radiation is in the yz plane).

Nirf
Posts: 6
Joined: Thu Oct 13, 2005 1:36 am

Postby Nirf » Mon Dec 04, 2006 1:55 am

I thought the test was relatively easy... I answered i think around 90, with less than 10 of those being guesses of any kind. It's funny though listening to you guys talk it's hard to even believe it was the same test, I don't remember hardly any of this. It could be because I was really short on sleep.
As for atomic energy, I thought that the energy goes as Z, not the square of Z.

I think frankly that the test is stupid. I got a good chunk of questions from topics covered in high school (like the optics and waves stuff); nobody does bloody nuclear physics and the bohr model of hydrogen anymore. That stuff is fossilized by now... The level of the questions when you know what they're talking about, is generally pathetic. Not one question where I had actually encountered the material in a course gave me any serious pause. I mean, no offense to whomever had trouble but look at the Lagrangian and Hamiltonian problem. If you ever took a course in classical mechanics, those problems are too easy to even be discussed. This is like a 5 minute example for a quick comparison between Newton's equation and Lagrangian/Hamiltonian dynamics. The actual problems in the course were far far harder. Same for the QM problems, and the majority of E&M problems. I feel bad for people with the circuits problems, i imagine a lot of physics people don't do hardly any circuits stuff (I'm in engineering physics so I've had multiple courses on analyzing simple circuit using phasor analysis and designing bandpass filters, etc). Really, the test is retarded in every way. The only reason I imagine schools look at it at all is because:
a) They have so many good applicants, that a poor score on this is one more way to narrow the pool quickly.
b) People who apply from schools that the university doesn't know and they want to know if the marks are BS or not. I can tell you from experience that 95's mean very different things at different schools. A lot of schools definitely offer courses the level of which (for a physics major) is pathetic. I know someone who's course in classical mechanics didn't cover poisson brackets! Half the reason you take CM is for the analogies to QM, and I think we can agree that that's a pretty vital one.

PS This isn't bitterness. I got 850 on a practice test the night before, and I got 850, and i studied a lot after that so I'm sure I did better this time. I don't think it'll stop me getting in anywhere. i just think this test is dumb.

artist
Posts: 68
Joined: Mon Nov 27, 2006 3:20 am

Postby artist » Mon Dec 04, 2006 10:43 pm

Nirf, I agree that the test is dumb. Except for me, it is bitterness.

astrobio
Posts: 27
Joined: Sat Dec 02, 2006 11:37 pm

Why I love ETS

Postby astrobio » Wed Dec 13, 2006 1:07 am

Today, Dec. 12 -- yes, 10 days after the test date! -- I received my practice physics test book from ETS. Now that's prompt service.

Anyone have a good idea of when scores by phone might be available? I can't wait to find out how I did. :P

somebody
Posts: 68
Joined: Tue Jun 13, 2006 4:25 pm

Postby somebody » Wed Dec 13, 2006 1:18 am

says january 4th on the website

schmit.paul
Posts: 161
Joined: Sat Nov 04, 2006 7:48 pm

Postby schmit.paul » Thu Dec 14, 2006 6:32 am

the nov. 4th test results were available a few days before the scores were supposed to be released for calling in and paying...just to give those of you that are still waiting for scores a little relief, if any




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