Energy of a Wave: Amplitude vs Frequency

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Discussion Overview

The discussion revolves around the relationship between the energy of a wave, its amplitude, and its frequency. Participants explore this concept in the context of different types of waves, including mechanical and electromagnetic waves, and consider how definitions and parameters may influence the understanding of energy transmission.

Discussion Character

  • Debate/contested
  • Conceptual clarification
  • Technical explanation

Main Points Raised

  • Some participants assert that the energy of a wave is related to its amplitude but not to its frequency, using the analogy of a swinging rope to illustrate potential energy transfer.
  • Others argue that the relationship between energy, amplitude, and frequency depends on the type of wave and the definitions used, questioning which wave is being discussed and what parameters are held constant.
  • One participant references information from Khan Academy suggesting that in mechanical waves, energy increases with amplitude but is independent of frequency and wavelength, while also noting the photoelectric effect where higher frequency light is necessary to release electrons, raising questions about the dependency of frequency on energy in that context.
  • Another participant clarifies that the usual meaning of "energy of a wave" refers to the energy transmitted per unit time, indicating that frequency may matter in mechanical waves, contrasting with electromagnetic waves.
  • There is a suggestion that the distinction between electromagnetic and mechanical waves may arise from the absence of a material medium for electromagnetic waves or from differing definitions of wave energy.

Areas of Agreement / Disagreement

Participants express differing views on the relationship between energy, amplitude, and frequency, indicating that the discussion remains unresolved with multiple competing perspectives presented.

Contextual Notes

Participants highlight the importance of defining the type of wave being discussed and the parameters considered, suggesting that assumptions about wave type and definitions may lead to different conclusions regarding energy relationships.

Lyakhnitskiy Dmitriy
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I need help with this question. The energy of wave related to its amplitude but not to frequency. If we talk about wave as disturbance carring energy we can imagine a swinging rope that gives potential energy to body by pushing it up. Bigger amplitude means getting high and increasing Potential energy of the body.
But bigger frequency means bigger amount of pushing the body up So the wave carries more energy.

P.S. Sorry for my bad English
 
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Lyakhnitskiy Dmitriy said:
The energy of wave related to its amplitude but not to frequency.
That depends on the type of wave, what you define as amplitude and the way you treat other parameters. Which wave do you mean and what is held constant?
 
mfb said:
That depends on the type of wave, what you define as amplitude and the way you treat other parameters. Which wave do you mean and what is held constant?
Amplitude is the biggest inclination from equilibrium position, I guess. Frequency is the number of occurrences of a repeating disturbance per unit of time. The thing is I got information about independency of energy of machenic wawe regarding to its frequency and wavelength from Khan Academy "Since the mediums are the same, we can focus on the wave energy increasing with the wave amplitude; not the frequency, wavelength or wave shape." But then I recognized photo effect when electrons need light of high frequency to be photo electrons. Electrons need more energy to be extricated from atom so is there depending between frequency and energy?
 
Lyakhnitskiy Dmitriy said:
The energy of wave related to its amplitude but not to frequency.
The usual meaning for "the engergy of a wave" would be the "energy per unit time" it transmits. Perhaps you saw the statement that this energy does not depend on the frequency of wave in the context of electromagnetic waves.

In mechanical waves, the frequency matters. For example, http://spiff.rit.edu/classes/phys207/lectures/waves/wave_energy.html

Perhaps somebody can comment of whether this distinction between E&M versus mechanical waves is due to the absence of a material medium for E&M waves or whtether it is due to using two different definitions for "the energy of a wave".
 
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