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    http://www.google.com/url?sa=t&rct=j...47008514,d.d2k

    I need help on question 2. The answer is B, but I can't understand HOW you know this. Can somebody please explain?

    Thanks a lot.
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    (Original post by krisshP)
    http://www.google.com/url?sa=t&rct=j...47008514,d.d2k

    I need help on question 2. The answer is B, but I can't understand HOW you know this. Can somebody please explain?

    Thanks a lot.
    Sound waves can't travel in a vacuum, they need a medium.
    So the statement B is the false one. Not only do they not travel faster in a vacuum, they don't travel at all.
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    (Original post by Stonebridge)
    Sound waves can't travel in a vacuum, they need a medium.
    So the statement B is the false one. Not only do they not travel faster in a vacuum, they don't travel at all.
    Okay thanks. Is it just because sound is longitudinal, so it only occurs when the air molecules vibrate parallel to direction of wave travel, but in a vacuum this cannot occur?
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    (Original post by krisshP)
    Okay thanks. Is it just because sound is longitudinal, so it only occurs when the air molecules vibrate parallel to direction of wave travel, but in a vacuum this cannot occur?
    It's more basic than that. In a vacuum there are no molecules so there can be no sound wave. The direction of vibration is irrelevant as there is no vibration.
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    (Original post by Stonebridge)
    It's more basic than that. In a vacuum there are no molecules so there can be no sound wave. The direction of vibration is irrelevant as there is no vibration.
    Thank you for the help
 
 
 
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