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    Please help with this question! here is the question and the mark scheme:

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    Mark scheme:
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    The part I don't understand is: path difference = 2 * distance moved
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    (Original post by Someboady)
    Please help with this question! here is the question and the mark scheme:

    Name:  physics3.png
Views: 99
Size:  20.9 KB

    Mark scheme:
    Attachment 530855530859



    The part I don't understand is: path difference = 2 * distance moved
    Can you please include a picture of Figure 1? as I believe this question is connected with harmonic/fundamental frequencies and I need to see the diagram to be sure
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    (Original post by sue99)
    Can you please include a picture of Figure 1? as I believe this question is connected with harmonic/fundamental frequencies and I need to see the diagram to be sure
    Sorry, my bad
    Name:  Physics33.png
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    Here's a link to the actual paper: http://filestore.aqa.org.uk/resource...-74071-SQP.PDF
    Its question 3.
    The markscheme can be found here: http://filestore.aqa.org.uk/resource...-74071-SMS.PDF
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    (Original post by Someboady)
    Sorry, my bad
    Name:  Physics33.png
Views: 70
Size:  69.0 KB

    Here's a link to the actual paper: http://filestore.aqa.org.uk/resource...-74071-SQP.PDF
    Its question 3.
    The markscheme can be found here: http://filestore.aqa.org.uk/resource...-74071-SMS.PDF
    The distance moved by the tube is d2-d1. The path difference is 2 times that because the wave travels that distance moved at the top of the tube and at the bottom of the tube
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    (Original post by veejn)
    The distance moved by the tube is d2-d1. The path difference is 2 times that because the wave travels that distance moved at the top of the tube and at the bottom of the tube
    Well you destroyed my confusion in one sentence....my teacher couldn't even tell me that! Bloody hell that was simple. Thanks very much!
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    (Original post by Someboady)
    Sorry, my bad
    Name:  Physics33.png
Views: 70
Size:  69.0 KB

    Here's a link to the actual paper: http://filestore.aqa.org.uk/resource...-74071-SQP.PDF
    Its question 3.
    The markscheme can be found here: http://filestore.aqa.org.uk/resource...-74071-SMS.PDF
    Okay, so this is how I understand it:

    for sound to be at a minimum at any point, the waves must have interfered destructively, ie. the path difference is a half number of wavelengths - lamda/2

    so wavelength = v / f
    = ....

    then because the path difference is lamda/2 , you just divide the value of the wavelength by 2
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    (Original post by sue99)
    Okay, so this is how I understand it:

    for sound to be at a minimum at any point, the waves must have interfered destructively, ie. the path difference is a half number of wavelengths - lamda/2

    so wavelength = v / f
    = ....

    then because the path difference is lamda/2 , you just divide the value of the wavelength by 2
    Yep so path difference is 0.2125m. As veejn mentioned above; the path difference is divided by two and this was what I didn't quite understand. It's because there's the top part of the tube and bottom part of the tube as seen in figure 1. That's why we divide by two since both lengths are equal and when we divide by two, we find the length of just one of the top/bottom part of the tube which is the length that the tubes been extended by.
    Thanks for your help! =)
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    (Original post by Someboady)
    Yep so path difference is 0.2125m. As veejn mentioned above; the path difference is divided by two and this was what I didn't quite understand. It's because there's the top part of the tube and bottom part of the tube as seen in figure 1. That's why we divide by two since both lengths are equal and when we divide by two, we find the length of just one of the top/bottom part of the tube which is the length that the tubes been extended by.
    Thanks for your help! =)
    Haha you're too nice; I didn't really help at all! But I'm glad you understand it now!
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    (Original post by Someboady)
    Well you destroyed my confusion in one sentence....my teacher couldn't even tell me that! Bloody hell that was simple. Thanks very much!
    No worries
 
 
 
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