The Official October 2012 Sat Subject Test Physics Thread

<p>yea i got 0.60 and T does not change. and for the question where it was talking abouyt a low energy neturon, was the answer because neturons do not have any charge?</p>

<p>What about that positively charged rod Q. Wasn’t it positive for both times - charging by induction and conduction?</p>

<p>Also a neutron is able to go near a nucleus because it’s neutrally charged?</p>

<p>Bohr experiment: “A few particles were reflected directly back toward the source”</p>

<p>Did anyone else get these answers?</p>

<p>@justPhysics, I got those answers. I don’t remember the positively charged rod question (I must’ve left it blank).</p>

<p>Also, for w/e reason, i put .4 as my answer because i figured it was 500-300 = 200. 200 is 2/5 of 500 = .4. Thought the question was more tricky than it actually was.</p>

<p>the one asking about energy was E: mc^2/sqrt(1-v^2/c^2). the total energy is defined as Y (gamma) * mc^2. Also the energy of the photons increased because the frequency increased, so hf increased.</p>

<p>@justPhysics, wasnt the question about the leaves being positively charged or not? I just said that the positivity of the elaves just increased only. </p>

<p>and yea " a few particles" because it wasnt even some i think. and </p>

<p>the neutron question is the same one that i am wondering about. but the answer " neutron has no charge" is true in any meaning. so shouldn’t that be the true one aka the answeR?</p>

<p>@injectmagic, what was the question?</p>

<p>A block is pulled at an angle of 37 degrees what is the acceleration?</p>

<p>a = (FCos(theta) / m)</p>

<p>The voltmeter needed to be in parallel and the ammeter in series.</p>

<p>@studytogo
That was a different question with the electroscope but the leaves or theta get large - increasing only.</p>

<p>@injectmagic
Oh I think your right, damn. Ok three wrong and 5 omitted; that is still an 800 right?</p>

<p>@Inject I got the same for the energy question. </p>

<p>@just I said because the neutron was neutrally charged, did anyone else say that?</p>

<p>@just I also said the leaves increase only.</p>

<p>-5 so far and 4 blank…based on the questions discussed thus far. there goes my 800.</p>

<p>Does anyone remember the question with the charged rod and the two spheres?</p>

<p>The answer choices looked like this:</p>

<p>Q Q
-Q +Q</p>

<p>or something. I’m pretty sure it was Q Q for both answers.</p>

<p>@justphysics yeah is was Q and Q. and then there was another question about it except one was grounded. I said none and none…not really sure. What did u guys put?</p>

<p>@just For the question with spheres, I said Q/2 for both I think.</p>

<p>@inject I said none and none also.</p>

<p>wait what was the initial charge before the sphere touched the other one?</p>

<p>@inject I thought it was Q on one sphere only. Maybe a different question though.</p>

<p>Wait, what was the none and none question? Remind me if you can remember the question.</p>

<p>Also for the change in kinetic energy as a particle (or something) moved around a circle was zero; the question had MR and 1/2(MR) and other distractors. I am pretty confident on that one.</p>

<p>@ambitious i think we both got it right but just don’t remember the charge well. What i did was divide the initial charge by 2.</p>

<p>The question asked if one sphere was charged Q and the other was neutral what was the resultant charge. i put both are Q/2
and yea the velocity was zero i got that wrong TT</p>

<p>Damn I think that’s another wrong. What on what question was the velocity zero?</p>