ATAR Notes: Forum
VCE Stuff => VCE Science => VCE Mathematics/Science/Technology => VCE Subjects + Help => VCE Physics => Topic started by: Shark 774 on May 23, 2011, 06:18:53 pm
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I just have no idea with the attached question... I picked D, which is wrong. Can somebody explain that correct answer(s)? I am not confident at all with photonic communication systems, any basic tips would be greatly appreciated, cheers.
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I just have no idea with the attached question... I picked D, which is wrong. Can somebody explain that correct answer(s)? I am not confident at all with photonic communication systems, any basic tips would be greatly appreciated, cheers.
If anything, it wouldn't be D. this is because at point P the signal has already been modulated (D could be an example of input signal)
I don't quite understand what they mean by 'single-frequency signal' but I'll assume this won't have anything to do with the Y-axis values (Therefore not C)
As point P is just before it is going to get demodulated, I believe it is still a pulsating light that is proportional to the information signal.
I'm going to go with A, but only because I don't understand what they mean by 'amplitude of light wave', and 'light intensity' makes more sense to me :S
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I'm quite sure that the intensity of light is somehow proportional to the amplitude of the light, so I'm guessing A and B
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I'm quite sure that the intensity of light is somehow proportional to the amplitude of the light, so I'm guessing A and B
The question does say "one or more" in bold... Therefore, they are probably expecting two answers. Thus, it would be A & B.
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The answer given was B and D and I think I just figured it out:
It can't be A, because you can't have negative light intensity. It wouldn't be C because there is no modulation in the wave. D could work because there is modulation and you CAN have a negative amplitude and B could work because there is modulation and no negative values. Or can you also not have a negative amplitude of a light wave? What do you reckon?
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The answer given was B and D and I think I just figured it out:
It can't be A, because you can't have negative light intensity.
*Facepalm* wasn't thinking straight. My bad!
I guess D could work, but I just keep thinking that the carrier wave must have a higher frequency than the input signal. Then again, we aren't given the characteristic of this input so thus it is possible that it is correct... I guesss..
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The answer given was B and D and I think I just figured it out:
It can't be A, because you can't have negative light intensity.
*Facepalm* wasn't thinking straight. My bad!
I guess D could work, but I just keep thinking that the carrier wave must have a higher frequency than the input signal. Then again, we aren't given the characteristic of this input so thus it is possible that it is correct... I guesss..
Yeah we weren't given the characteristics, and there is no scale on the time axis so there is nothing to say that it isn't high frequency. Thanks for your response.