<p>Hey guys, I've been taking practices and have found some questions to be especially difficult. I will post it and we should create a pool of difficult questions considering some questions have conceptual knowledge not given in review books.
Fact- An object's charge is ALWAYS a multiple of an electrons charge-1.6x10^19 </p>
<p>Protons are found in the nucleus of theatom. The nuclear protons with the greatestmass are located
(A)in the hydrogen atom.
(B)in the carbon atom.
(C)in the iron atom.
(D)in the radon atom.
(E)in the uranium atom</p>
<p>When
U -235 is fissioned in a nuclear reactor, the nuclear reaction is maintained by
(A)heat produced in the reactor.
(B)the moderator rods.
(C)radioactive decay products.
(D)vibrations induced in the U -235.
(E)neutrons produced in the reaction.</p>
<p>Keep in mind I’m not an expert, but if I were taking the test, I would hazard a guess as to</p>
<ol>
<li><p>A, because according to mass energy equivalence, the mass of a proton plus the mass of a neutron is greater than the mass of one hydrogen atom. If you carry this process on up the periodic table, the individual proton masses would just go down.</p></li>
<li><p>E, pretty sure about this one, the neutrons spring off and get absorbed and nuclear chain reactions etc.</p></li>
</ol>
<p>someone tell me why I got A wrong, cause I probably did</p>
<p>nope you got it right.</p>
<p>What’s the curve to get an 800, what raw score should we be looking for, I have barrons and it’s really hard, my best score was a 61.</p>
<p>do you have more examples? also can you exapain the first one</p>
<p>I’m not sure what either of the questions exactly mean…</p>
<p>is the 2nd one asking what keeps the reaction from going out of control (moderator rods) or what causes the reaction (neutrons) ???</p>
<p>well a 65> is good. the second questions asking what keeps the reaction going on. Why doesn’t it stop after the first atom.
first question:
Due to the mass that is converted inthe nucleus (mass defect) to hold the protons together in thenucleus, the proton does not have the same mass when it isinside the nucleus as it has outside the nucleus. The hydrogenproton is the proton that is least affected because it is the only proton in the hydrogen atom.</p>
<p>A radioactive isotope of iodine has a half-life of 8 hours and causes a counter to register 180 counts/min. Find the count rate for this sample of iodine two days later.
(A)1.4/min
(B)2.8/min
(C)5.6/min
(D)11.2/min
(E)22.4/min</p>
<p>Assuming the counts are proportional to the amount of sample remaining, I’m guessing B.</p>
<p>yup you’re right.</p>
<p>38.A very rich boy has an ice hockey practice floor that is essentially frictionless installed in a long refrigerated boxcar. As the train is moving, the boy practices shooting at the goal at the other end of the car. Just as he releases his shot, the train goes around a sharp curve to the left (looking forward in the direction the boy is shooting). Which statement most accurately describes the boy’s shot?
(A) It curves to the right and misses tothe right side of the net.
(B) It curves to the left and misses to theleft side of the net.
(C)It travels straight and misses to theright side of the net.
(D)It travels straight and misses to theleft side of the net.
(E)It travels straight into the goal.</p>
<p>eswara: C. because it is frictionless floor the puck wont be effected by the train turning, but because the train is turning to the left, so does the goal and he will miss to the right.</p>
<p>gotcha.
A physicist shines coherent light through an object, A, which produces a pattern of concentric rings on a screen, B. A is most likely:
(A) A polarization filter
(B) A single-slit
(C) A multiple-slit diffraction grating
(D) A prism
(E) A sheet with a pinhole</p>
<p>Hi!
I’m going to join this discussion!!</p>
<p>So quick questions about the test:
I just found out that if the gravitational force between 2 planets is F and you double the diameter of one planets the grav force is still constant. Can someone verify this?</p>
<p>The explanation was that because only the diameter is increasing and not the distance in between the centers of mass of the planets that F grav would not be affect. This makes lots of sense, but considering that this was an actual SAT2 test question by the college board, I feel like its a trick question… Do they ask a lot of these types of questions?</p>
<p>Also is there a lot of stuff on the test about Joule’s law, superposition, special relativity, superconductivity, chaos theory, and astrophysics?? They have those down in the released test breakdown… but from practice tests that I’ve seen I don’t see a lot of these types of questions</p>
<p>yuki: (G<em>M</em>m)/r^2</p>
<p>this is the formula and no where does it mention the radius of the planet. r = the distance between the 2 planets. Although I think the distance does measure from the center of mass/ centenr of mas, but usually if they say the distance doesn’t change then yeah, it wil be the same…</p>
<p>Good luck to everyone doing the test tomorrow! Hopefully one of these questions appear and its good we went over it :).</p>
<p>^ :O, that question was there…
I got it wrong :(</p>
<p>I found this test harder than any practice tests I’ve done… What did u guys think? Let’s discuss some difficult questions… Hope the curve is lenient.
Also, does Collegeboard always reuse past questions like they did this time??</p>
<p>@wlsnehf yeah, even I thought it was a little harder, the Princeton tests are supposed to be accurate, but this one was harder than the PR tests…
That’s my opinion anyway… What about you lot? How did it go?</p>
<p>Can anyone recall difficult questions…?</p>
<p>Guys I’m crying right now, what was up with that test!?! I didn’t know anything and I basically left half the test blank!</p>
<p>Hard questions in my opinion:
Solenoid question
Positive plate and electron question
Falling through vacuum
Question about why sounds gets less loud as it move away
Basically all the match up questions
Question about person not involved in light and sound…
Yeah I royally failed that 
I super disappointed since I was getting 780-800 on PR, barrons, and Kaplan tests… sigh</p>
<p>Also before I forget what was the answer for the water tank question? The question about inertial frames in the train car, and also the 44m question</p>
<p>Can someone else confirm that? I put air resistance, but I don’t think that makes much sense now since the air resistance would apply to every trial…</p>