Editing Resonance (section)

{{Short description|Physical characteristic of oscillating systems}}
{{About|resonance in physics}}
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[[File:Resonance.PNG|thumb|upright=2|Increase of amplitude as damping decreases and frequency approaches resonant frequency of a driven [[Damping ratio|damped]] [[simple harmonic oscillator]].{{sfn|Ogata|2005|p=617}}{{sfn|Ghatak |2005|p=6.10}}]]

'''Resonance''' is a [[phenomenon]] that occurs when an object or [[system]] is subjected to an external force or [[vibration]] whose [[frequency]]  matches a '''resonant frequency''' (or '''resonance frequency''') of the system, defined as a frequency that generates a maximum amplitude response in the system.  When this happens, the object or system absorbs energy from the external force and starts vibrating with a larger [[amplitude]]. Resonance can occur in various systems, such as mechanical, electrical, or acoustic systems, and it is often desirable in certain applications, such as musical instruments or radio receivers. However, resonance can also be detrimental, leading to excessive vibrations or even structural failure in some cases.<ref>{{Cite book |last=Taylor |first=John R. |title=Classical Mechanics |date=22 January 2023 |publisher=University Science Books |publication-date=1 March 2003 |pages=187}}</ref> 

All systems, including molecular systems and particles, tend to vibrate at a natural frequency depending upon their structure; when there is very little damping this frequency is approximately equal to, but slightly above, the resonant frequency. When an [[Oscillation|oscillating]] force, an external vibration, is applied at a resonant frequency of a dynamic system, object, or particle, the outside vibration will cause the system to oscillate at a higher [[amplitude]] (with more force) than when the same force is applied at other, non-resonant frequencies.{{sfn|Halliday|Resnick|Walker|2005|p=324}}

The resonant frequencies of a system can be identified when the response to an external vibration creates an amplitude that is a [[relative maximum]] within the system.{{sfn|Halliday|Resnick|Walker|2005|p=324}} Small periodic forces that are near a resonant frequency of the system have the ability to produce large amplitude [[oscillation]]s in the system due to the storage of [[vibrational energy]].

Resonance phenomena occur with all types of vibrations or [[wave]]s: there is [[mechanical resonance]], [[orbital resonance]], [[acoustic resonance]], [[Electromagnetic radiation|electromagnetic]] resonance, [[nuclear magnetic resonance]] (NMR), [[electron paramagnetic resonance|electron spin resonance]] (ESR) and resonance of quantum [[wave function]]s. Resonant systems can be used to generate vibrations of a specific frequency (e.g., [[musical instrument]]s), or pick out specific frequencies from a complex vibration containing many frequencies (e.g., filters).Some recent theoretical models explore resonance as a unifying structure across quantum, gravitational, and cosmological scales, proposing phase alignment rather than time as the key organizing principle.<ref>Kanda, Yu. "Theory of Resonance – Series Index", Zenodo, 2025. https://doi.org/10.5281/zenodo.15522546</ref>

The term ''resonance'' (from [[Latin]] ''resonantia'', 'echo', from ''resonare'', 'resound') originated from the field of acoustics, particularly the [[sympathetic resonance]] observed in musical instruments, e.g., when one string starts to vibrate and produce sound after a different one is struck.