Multiple Choice (Compiled Answers) (1 Viewer)

[crazybrad]

i got 9!!!!
me fucked

 

[Bannanafish]

read my explanation in the other thread

 

[~TeLEpAtHeTiC~]

13/15
meh i made up for it in short answer

 

[Owen]

Question 5 has to be (D)!!!!
The question was asking what the time was for the stationary observer.
Time goes slower when near speed of light.
Therefore the only answer which is bigger than the time recorded at high speed is (D)
The time cannot be less than 10yrs.

 

[juber]

Originally posted by ssssonicyouth
but people who get high marks become lawyers-- so the ability to be anal retentive is actually quite important

Edit: with the photoelectric question- it seems like most people r putting d- and if the majority of band six people put a wrong answer, then they just go 'oh, the question was messed up' and scrap it. I have a feeling it'd be quite likely with this one.

well the "majority of band 6 people" are wrong.

There really shouldn't be many band 6 people who put B as they would have realised its invalid. Perhaps the only call is that those who had no idea of anything about the question would have put down D as a guess, whereas those people who put B would have put it because they knew about the question but were just jumped the gun a bit before really thinking about it.

They shouldn't scrap the question.

I just think that it was stupid because it will probably be mainly band 6 students putting B because band 5/4/3/2/1 students wouldn't know that the glass was put in between to stop the radiation, and would have guessed D (or any of the others i suppose)

 

[freaking_out]

Originally posted by Owen
Question 5 has to be (D)!!!!
The question was asking what the time was for the stationary observer.
Time goes slower when near speed of light.
Therefore the only answer which is bigger than the time recorded at high speed is (D)
The time cannot be less than 10yrs.

lol, go c that other thread....it can b argued its B!!!

 

[Bannanafish]

mwuhahaha i'll take all you non believes on!
argue in the other thread if you dare

 

[deyveed]

Ok. Does anyone have a set of answers (without any controversial ones)?
Plz post because i'm confused.

 

[toknblackguy]

let's go bannanafish
oh well - i emailed a harvard professor, and his initial reply tore down the damn question!
oh well..i replied back, we'll see

 

[toknblackguy]

a transcript of the email:
Re: Time Dilation
Jason,

How do you define "when" in
> when seen from the astronauts's spaceship

In working out the answer to this question you will get the answer.
How do you define spatially separated but simultaneous events?

--Edward L. (Ned) Wright, Professor of Physics and Astronomy
310-825-5755, FAX: 310-206-2096, www.astro.ucla.edu/~wright/intro.html
Mail: UCLA Astronomy, PO Box 951562, Los Angeles CA 90095-1562
FedEx: Math Sciences 8951, UCLA Astronomy, 405 Hilgard Ave, LA CA 90024

On Sat, 1 Nov 2003, Jason Tokn wrote:

>hi. i'm a year 12 student who just sat the hsc in australia, and i have a
>question regarding the relativity of time.
>the multiple chouice question 5
>an astronaut set out in a spaceship from earth orbit to travel to a distant
>star in our galaxy. the spaceship travelled at 0.8 c. when the spaceship
>reached the star the on board clock showed the astronaut that the journey
>took 10 years.
>an identical clock remained on earth. what time in eyars had elapsed on this
>clock when seen from the astronauts's spaceship?
>A 3.76
>b 6
>c 10
>d 16.7
>
>i put b, because it was my understanding that from the astronaut's
>perspective, the earth is moving away from the astronaut at 0.8c, and hence
>in the "moving" frame, time should go slower. could you please provide us
>with the correct answer, and a simplistic explanation.
>thank you.

 

[tezzat85]

Hey guys, for question 10, i know a lot of ppl put A as their answer and it's also the answer I was gonna choose IF i'm certain that C is wrong, but i'm not...
ok think about this...'forces between parallel current-carrying conductors', but how da fcuk is the loop on the table parallel? for parallel lines, they have to be straight and they're not! so I thought even if the current was switched on, there'd simply be no effect on the loop.
As i said i'm really tossing between A and C but i would really like to put my money on C and firstly that's what I put, and secondly, i thought that might be a band 6 question that most of the state would get wrong.

 

[Constip8edSkunk]

the parallel line thing u alluded to is an effect just like this question. the cause is the magnetic field induced by the current. if you consider the field of the conducting wire, you'll find that the ones inside will repel eachother, hence pushing the wire outwards.

 

[SmokedSalmon]

Q14 queries:

I agree that the glass stops UV. However, the diagram in the question doesn't show a UV source. If the source is on the right of the picture then the glass has no effect or a marginal increase in the size of the spark (by reflection).

 

[helper]

The spark gives off UV. The amount of UV reaching the coil is less. Therefore a smaller spark.

How much smaller is really a question as there are other sources of UV.

 

[theone123]

ahhhh i stuff dat question up again