Why is any wave defined by the wavelength, but not by the amplitude?

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Discussion Overview

The discussion revolves around the characteristics that define waves, specifically focusing on why waves are typically identified by their wavelength or frequency rather than amplitude. Participants explore the implications of these definitions in various contexts, including physics and wave phenomena.

Discussion Character

  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • Some participants assert that waves are identified by wavelength or frequency because these parameters relate to observable phenomena such as color and pitch, while amplitude primarily affects intensity.
  • One participant draws an analogy between the properties of atoms and waves, suggesting that just as the number of protons defines an element, frequency defines the properties of a wave, whereas amplitude is less critical for comparison.
  • Another participant notes that amplitude does not require two wave trains for definition, implying that it could also describe a wave, but emphasizes that frequency provides more information about wave motion.
  • There is a suggestion that the focus on frequency over amplitude may stem from the need to observe wave motion, which is more informative than a static measurement of amplitude.

Areas of Agreement / Disagreement

Participants express varying viewpoints on the importance of amplitude versus frequency in defining waves. While some agree on the significance of frequency, others highlight the role of amplitude, indicating that the discussion remains unresolved with multiple competing views.

Contextual Notes

Participants mention that amplitude is important but often secondary to frequency in discussions about wave properties. There is also a suggestion that the context of wave motion influences the preference for using frequency as a defining characteristic.

Soumen2010
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Any wave is identified by its wavelength (or frequency), and the wavelength is the distance between the two consecutive crests (or troughs) in wave trains. But wave is not identified by its amplitude. The wave could have been described by the amplitude as it doesn't require two wave trains (or wave pulses). Can anybody explain why so?
 
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Soumen2010 said:
Any wave is identified by its wavelength (or frequency), and the wavelength is the distance between the two consecutive crests (or troughs) in wave trains. But wave is not identified by its amplitude. The wave could have been described by the amplitude as it doesn't require two wave trains (or wave pulses). Can anybody explain why so?

That's not something I've ever considered. I suspect that the choice has to do with the phenomena that we focus on and what causes them. Color of light and pitch of sound are both a matter of frequency. Frequency is also at the heart of the Doppler effect and and beating. Amplitude primarily affect intensity...no other phenomena leap to mind.
 
Agree with Fewmet.
 
The frequency determines the properties of the wave. The amplitude just determines the magnitude of those properties. Knowing that two waves have equal amplitude, but different frequency doesn't really tell you a whole lot about how similar those waves are.

To use an analogy, in an atom the number of protons determines the properties of the element, and is thus used to describe the atom. On the other hand, the number of atoms is similar to amplitude of the wave. While knowing how many atoms you have is certainly important, it is more important to know what kind of atoms you have first.
 
Soumen2010 said:
Any wave is identified by its wavelength (or frequency), and the wavelength is the distance between the two consecutive crests (or troughs) in wave trains. But wave is not identified by its amplitude. The wave could have been described by the amplitude as it doesn't require two wave trains (or wave pulses). Can anybody explain why so?

well your question has the answer ! amplitude dosent require 2 wave trains ! the simple fact that often people are interested in motion of wave makes us "use" more often the terms frequency...
lemme xplain this. for describing amplitude you would just be done with a photograph of the wave . but insted if you want to know the frequency , you would need to see the wave moving ! and thus people could get more information out from frequency but people do use amplitude too...for defining a wave you surely need amplitude, its angular velocity and phase
y = A sin(\varpi*t + \varphi)...
 

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