ATAR Notes: Forum
Archived Discussion => 2010 => End-of-year exams => Exam Discussion => Victoria => Physics => Topic started by: Chavi on November 10, 2010, 03:05:46 pm
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How'd everyone find it? I thought it was relatively straightforward (except for 1 question).
here are my answers (off the top of my head)
1.B
2.D
3.A
4.C
5.C
6.D
7.C
8.C
9.A (not sure about this one, becuase the flat region was at 0DB)
10.B
11.A
12.D
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wasn't question 9 from 2000 hz - 10000 hz? i thought that was pretty straight forward
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wasn't question 9 from 2000 hz - 10000 hz? i thought that was pretty straight forward
But the debate is whether the flat part is included or not. . .
I also had D originally, but the next question follows on with a 1000 hz response, thus eliminating D)
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It's B I believe, fidelity is the flat region. The decibel values are relative, a response of 0db simply means it's equal intensity to whatever they measured it against.
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It's B I believe, fidelity is the flat region. The decibel values are relative, a response of 0db simply means it's equal intensity to whatever they measured it against.
That is what I got as well. You just had to give the range of the flat region.
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ok, what answer was B?
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9
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Right, but there was better response for 2000 - 10000 herz
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yes, but what was correct range exactly? 2000 - 10000 hertz or something else?
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How'd everyone find it? I thought it was relatively straightforward (except for 1 question).
What was question 1? I can't remember it...
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Fidelity is about a consistent response. A microphone that responds very well to 10,000Hz but poorly to 9,000Hz is useless as changing frequency slightly would also change the volume. You can always turn the microphone up super high if it's too low, so long as the intensity is constant for all frequencies.
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haha . wasn't question one like speed over wavelength or frequency to get the other one?
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How'd everyone find it? I thought it was relatively straightforward (except for 1 question).
What was question 1? I can't remember it...
Question 1:
Find the wavelength. Speed of sound = 330m/s, f=512 hz
Lamda = 33/512 = 0.64 so, option B
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Fidelity is about a consistent response. A microphone that responds very well to 10,000Hz but poorly to 9,000Hz is useless as changing frequency slightly would also change the volume. You can always turn the microphone up super high if it's too low, so long as the intensity is constant for all frequencies.
This.
Fidelity is about having consistent response over a range of frequencies, I believe.
EDIT:
How'd everyone find it? I thought it was relatively straightforward (except for 1 question).
What was question 1? I can't remember it...
Question 1:
Find the wavelength. Speed of sound = 330m/s, f=512 hz
Lamda = 33/512 = 0.64 so, option B
So why was it tricky??
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Not question 1 - but one of the question (q9)
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Not question 1 - but one of the question (q9)
Can you explain what your reasoning was?
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Not question 1 - but one of the question (q9)
Can you explain what your reasoning was?
All portions of the graph above 0DB
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Not question 1 - but one of the question (q9)
Oh lol, misread it.
And with question 9 you had to take the flat section of the graph. The definition of fidelity with reference to sound is "accuracy with which an electronic system reproduces the sound or image of its input signal". Thus you don't want any fluctuation in the output across different frequencies.. So you take the flat part.