antinode
(noun)
A region of maximum amplitude situated between adjacent nodes of a vibrating body, such as a string
Examples of antinode in the following topics:
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Sound Production: Vibrating String and Air Columns
- Closed Air Tubes:The maximum displacement of the air occurs at the open end of the tube, and is called the antinode.
- The distance from the node to the antinode is 1/4 the length of one wavelength, and equal to the length of the tube, as shown in this equation:$\lambda = 4L$This can also be seen in this figure: The frequency is equal to the speed of sound in the air divided by the wavelength, or:$f=\frac {v_w}{\lambda}=\frac {v_w}{4L}$, where vw is the speed of sound in the air, which we learned how to find in a previous atom.
- They are very similar to the ones we talked about above, but there is an antinode at both ends, since they are both open, as shown in this figure: Since there is an antinode at both ends, we can see that the length of a wavelength is found by this equation: $\lambda = 2L$And the frequency can be found in the following equation:$f=\frac {v_w}{\lambda}=\frac {v_w}{2L}$
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Standing Waves on Strings
- All standing waves have places, called nodes, where there is no wave motion, and antinodes, where the wave is largest.
- The spots at the biggest part of the wave - where there is the most change during each wave - are called antinodes.
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Standing Waves in Air Columns
- When a standing wave is formed in a tube, the standing wave has a maximum air displacement at the open end called an antinode.
- The distance from a node to antinode is 1/4 of a wavelength, and is equal to the length of the tube.
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Standing Waves and Resonance
- The word antinode is used to denote the location of maximum amplitude in standing waves.
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Standing Waves on a String
- The points which reach the maximum oscillation height are called antinodes, and are results of complete constructive interference.
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Reflections
- The points which reach the maximum oscillation height are called antinodes.