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Homework Help: Wavelength True/False

  1. Mar 6, 2005 #1
    (True / False) A straight wave heads into a curved surface. It will reflect so that the wave scatters

    (True / False) When a straight wave pases through a small opening, it produces a small straight wave.

    (True / False) Unless it is disturbed each point on a wave will travel along either a straight or curved path.

    (True / False) When an wave hits a barrier, the angle that it reflects depends on its speed.

    (True / False) As a wave changes media its speed changes.

    (True / False) Two waves traveling through the same medium meet, they will bounce off each other and change direction.

    (True / False) The speed of a wave is determined by its medium.

    (True / False) Defraction is the bending of a wave because its speed changes.

    (True / False)As the frequency of a wave increases, its wavelength increases.

    (True / False) During refraction, a wave bends because it hits the edge of a barrier.

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    Here's my best answers for all of them.

    1. T - a curved surface will make a wave bend
    2. T - a small opening will make the wave be small
    3. F - it will travel on a straight path if undisturbed
    4. F - the angle depends on the barrier angle
    5. T - speed is determined by media
    6. F - the two waves will not necessarily change direction
    7. T - speed is determined by media
    8. F - diffraction is bending because of a barrier
    9. F - frequency and wavelength are inversely related
    10. F - refraction bends a wave because of media change
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    Many thanks,
    Jameson
     
  2. jcsd
  3. Mar 7, 2005 #2
    What is this wave, water, light, sound what?
     
  4. Mar 7, 2005 #3

    HallsofIvy

    User Avatar
    Science Advisor

    (True / False) A straight wave heads into a curved surface. It will reflect so that the wave scatters
    True but because a curved surface "spreads" out the wave- so it scatters. Even a straight surface will cause a wave to "bend"- that's not scattering.

    (True / False) When a straight wave pases through a small opening, it produces a small straight wave.
    False! A small opening acts like a "point source" the wave spreads out in circles.

    (True / False) Unless it is disturbed each point on a wave will travel along either a straight or curved path.
    ? But it says "straight or curved path"! that's certainly true. Frankly I don't like the reference to a "point on a wave"- I assume this refers to a ray, but that's not clear. Anyway, if a water wave, for example, travels over a sloping bottom it will curve. Is that "disturbed" or not? Bad question in my opinion.

    (True / False) When an wave hits a barrier, the angle that it reflects depends on its speed.
    False. a wave will always reflect to make equal angles with the barrier.

    (True / False) As a wave changes media its speed changes.
    In general that's true. Of course, it is possible that two "different" media give the same wave speed.

    (True / False) Two waves traveling through the same medium meet, they will bounce off each other and change direction.
    False, they pass right through each other.

    (True / False) The speed of a wave is determined by its medium.
    True- as long as "medium" is understood to include the depth as well as the density of the liquid for waves in liquid.

    (True / False) Defraction is the bending of a wave because its speed changes.
    ?? True- if the word was supposed to be "refraction", false if "diffraction". Bending because of a barrier is "reflection".

    (True / False)As the frequency of a wave increases, its wavelength increases.
    False, they are inversely proportional.

    (True / False) During refraction, a wave bends because it hits the edge of a barrier.
    False- that's "reflection". But why did you answer the opposite way in question 8?
     
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