ATAR Notes: Forum
VCE Stuff => VCE Science => VCE Mathematics/Science/Technology => VCE Subjects + Help => VCE Physics => Topic started by: maxleng on November 13, 2007, 04:46:45 pm
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im thinking there will be a graph sketching Q tomorrow..
im not 100% sure on this, heres a Q from the 2004 sample exam (thers no answers even on itute)
(http://i71.photobucket.com/albums/i127/retroflector/physicsss.jpg)
is my graph right?
also could someone PLEASE explain Q 10 2004 exam1 its another graph Q
edit: is the voltage graph just the current graph but a reflection in the x-axis?? thats what ive been told
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shouldnt that graph be a sine curve?
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Not really. You've got the basics down - where your maximum and minimums are going to be.
But your curve should take a sine wave shape, not blocky.
Edit: Beaten to it :oops:
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oh yeah i see now, it cant really be a flat line as the flux doesn't stay constant at any time :idea:
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exactly :D
Flux is always changing at a rate of BAcos(theta)...or is it BAsin(theta) ... so while the coil is rotating, the amount of flux is dependant on a cos... or uh sin graph.
it doesnt really matter, as long as you take 0 as 0... so probably sin graph.
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Question 11
Which one of the following statements correctly describes the effect on the pattern if the distance
between the two parallel slits is increased.
A. The pattern remains the same.
B. The bright bands move closer together.
C. The bright bands move further apart.
lisachem answers say the answer is C
People's thoughts...
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the pattern remains the same.
youre not changing gap width, nor wavelength, therefore diffraction is the same.
The only difference is the waves have further to travel before they interfere.
(this MAY mean a slight slight slight change in intensity, but not really lol)
answer is A
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Question 11
Which one of the following statements correctly describes the effect on the pattern if the distance
between the two parallel slits is increased.
A. The pattern remains the same.
B. The bright bands move closer together.
C. The bright bands move further apart.
lisachem answers say the answer is C
People's thoughts...
According to the formula: Spacing = wavelength x distance betw. screen & slits / dist. betw. slits, W=lambda x L / d
If you increase dist betw. slits, the denominator decreases, so spacing increases. Answer C
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the "distance between" the two parallel slits is increased.
If w = (lambda * Length) / (distance between slits)
increasing distance would mean w decreases, therefore the bright bands move closer together.
Is this right?
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When the flux is a maximum the volt should be 0 and vice versa.
The cos theta thing isn't in the course, and hence I never bothered to learn it xD
avogarbro - I agree with you :)
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thank you cara.mel. I wanted to make sure because ther are so many mistakes in the lisachem solutions of 2005.
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oh, maybe i was wrong ... :oops:
never seen that formula
thnking about it practically, i cant see how the distance between the sources makes a difference :(
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oh, maybe i was wrong ... :oops:
never seen that formula
thnking about it practically, i cant see how the distance between the sources makes a difference :(
Cheat sheet it!
And also for single slit, 2x = lambda * l/ w (pretty similar I know, l= length to screen, w = width of slit, 2x is the central maximum because its twice as big as all the other ones) I shall go check if thats right after posting but I'm pretty sure it is
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I cant believe we havent learnt this :S:S:S
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Question 11
Which one of the following statements correctly describes the effect on the pattern if the distance
between the two parallel slits is increased.
A. The pattern remains the same.
B. The bright bands move closer together.
C. The bright bands move further apart.
lisachem answers say the answer is C
People's thoughts...
According to the formula: Spacing = wavelength x distance betw. screen & slits / dist. betw. slits, W=lambda x L / d
If you increase dist betw. slits, the denominator decreases, so spacing increases. Answer C
this is correct
i have all the possibilities and what happens when each thing changes on my 1337 sh33t :P
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Oooh nice, could you pplleeeassseeee post them maxleng?
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For double slit and single slit diffraction patterns, am i right in saying that when referring to intensity it is the frequency of light bands that appear?
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this is what i get with the question:
considering the initial position as positive flux, the flux-time graph would look like:
(http://img232.imageshack.us/img232/8503/fluxtimeof5.jpg)
since emf-time graph is the -ve gradient graph of the flux-time, this gives:
(http://img232.imageshack.us/img232/9051/emftimeto8.jpg)
i think thats correct...
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Basically, you shift the sine/cosine graph 1/4th to the right. :)
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Thats true, but if you have a explain question you have to talk about it in, t would be best not to say tha t lol
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the "distance between" the two parallel slits is increased.
If w = (lambda * Length) / (distance between slits)
increasing distance would mean w decreases, therefore the bright bands move closer together.
Is this right?
WHOOPS! :oops: I meant by increasing distance you INCREASE the denominator, and W decreases. Silly me! I've been on a bad spate of arithmetic and logical whimsies since methods 2.