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Section I - Multiple Choice (1 Viewer)

kiinto

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This is possibly the worst reasoning ever. Both A and C are semiconductors.
+1. Word for word what I was going to post.

I still think it's A. Even if the BoS says it's B, I still think it's A. I mean, what if we're trying to detect thermal radiation from a particularly cold person (he's been plowing the snow fields of siberia). Peak wavelength would be down and to the right ---> InSb semiconductor won't be as effective ---> HgCdTe is better for the job.
 

someth1ng

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+1. Word for word what I was going to post.

I still think it's A. Even if the BoS says it's B, I still think it's A. I mean, what if we're trying to detect thermal radiation from a particularly cold person (he's been plowing the snow fields of siberia). Peak wavelength would be down and to the right ---> InSb semiconductor won't be as effective ---> HgCdTe is better for the job.
That's partly like my logic - I just feel that they are both valid ways though. I only believe B because it is able to detect more. It was a rather poor and ambiguous question that was written.
 

imsleepyz

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Hey guys, for question 13, I didn't use Kepler's Law of Periods. Instead I used v=2(pi)r/T and used the velocity from question 12. And so I got C for q. 13. Why is this method wrong, will someone tell me please?
 

mickstarify

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Hey guys, for question 13, I didn't use Kepler's Law of Periods. Instead I used v=2(pi)r/T and used the velocity from question 12. And so I got C for q. 13. Why is this method wrong, will someone tell me please?
ok so v = 2pi*r / T, I cant find any v from the first question but anyway you can't use v from anywhere, at different orbits there will be different orbital velocities (it is not constant, unlike r^3/t^2) and as such you can't just sub it into other equations
 

imsleepyz

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ok so v = 2pi*r / T, I cant find any v from the first question but anyway you can't use v from anywhere, at different orbits there will be different orbital velocities (it is not constant, unlike r^3/t^2) and as such you can't just sub it into other equations
I used the equation v=sqrt((GM)/r). That's how I worked out centripetal force in question 12.
I know it sounds like a very long way of doing question 13 but I'm just wondering why i don't get the same answer as you would get using Kepler's Law of Periods... Thanks though!
 
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Danstar2

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I'll admit it was a hard MC, I'm hoping for around 15, worst case 13+, I doubt I went that wrong though. :cry:
Averaging out from what I can see here there are definitely 3 I did wrong.
 

Heydosaurus

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I screwed multiple choice so bad. I'm looking at 12/20 tops. I have no real dramas with this, however, as I'm extremely confident that I blitzed the rest of the paper (excluding Angry Birds, because I'm a retard). Hopefully I can pull out a good 80/100 raw, although I will be very content with anything in the seventies, considering my rather crappy (61% raw) trial result. Multiple choice in Physics has always been my bizarre downfall. In the trial, which I believe was based off of the CSSA trial, I got 6/20 for the multiple choice questions.
 

kdizzler

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18/20 can't complain, it was a hard MC
and for the last question (I got it wrong), but all 4 are semi conductors because conductors have a band gap of 0 eV, and insulators are generally >10eV
the induced EMF question, It's definitely D, as you take the gradient and reverse the direction (Back EMF), had the identical question the the trial coincidently got wrong
 

Nooblet94

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1-D
2-A
3-C
4-C
5-C
6-C
7-B
8-A
9-B
10-D
11-C
12-A
13-B
14-C
15-D
16-A
17-B
18-C
19-D
20-B

How many mistakes? :(
 

NickGero

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Wow I actually got 20/20 for M.C. -.-

Here's to hoping I didn't screw the rest of the test up.
 

xmichaelpham

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These were my answers; please check

1. d
2. a
3. c
4. b
5. c
6. c
7. b
8. a
9. b
10. d
11. c
12. a
13. b
14. d
15. d
16. a
17. b
18. c
19. d
20. b
 

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