What is the definition of wave speed?

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Discussion Overview

The discussion revolves around the definition of wave speed, specifically addressing both progressive and standing waves. Participants explore various interpretations and nuances of wave speed in different contexts, including theoretical and practical applications.

Discussion Character

  • Conceptual clarification, Debate/contested

Main Points Raised

  • One participant suggests that the speed of a progressive wave can be defined as the rate at which energy is transferred by the wave.
  • Another participant defines the speed of a standing wave as stationary in position, referencing an external source for clarification.
  • A participant distinguishes between different types of wave speeds: phase velocity for simple sine waves, group velocity for wave packets, and notes that standing waves have a speed of zero but a non-zero frequency.
  • One participant proposes that the speed of a stationary wave could be defined as the speed of either the incident or reflected wave that creates it, citing a marking scheme as support.

Areas of Agreement / Disagreement

Participants express differing views on how to define the speed of standing waves, with some asserting it is zero while others suggest it can be defined in relation to the incident or reflected waves. The discussion remains unresolved regarding a singular definition.

Contextual Notes

Participants reference external sources and marking schemes, indicating that definitions may depend on specific contexts or educational frameworks. There is an acknowledgment of the complexity in defining wave speed across different types of waves.

Who May Find This Useful

This discussion may be useful for students preparing for examinations or individuals seeking to understand the nuances of wave speed in physics.

ShudyShab
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Hi :) I just want to know how you would simply define the speed of a wave in words?
Because I often get questions asking to define the speed of a standing wave etc.

One of the definitions I know for progressive wave is the rate at which energy is transferred by a wave.

but what about the speed of a standing wave?
 
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Speed can mean different things.

1. The speed of a simple sine wave is the distance that each peak of the sine curve shape travels in a given amount of time (phase velocity).

2. The speed of a wave packet is the distance that the peak of the wave packet's envelope curve travels in a given amount of time (group velocity). Energy travels at the group velocity.

3. In non-scientific usage, "speed" may also refer to the rate in time at which a fixed point in space waves on and off. In science, we call this the "frequency" of the wave, not the "speed".

So, a standing wave has a speed of zero, because the peaks do not travel, but has a non-zero frequency, because points are still waving on or off (or up or down for transverse waves). Take a look at my http://faculty.uml.edu/cbaird/95.658%282011%29/Lecture3.pdf" for a more rigorous explanation.
 
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Thank you :) I'll check out all the links
 
can't we define the speed of stationary wave as follows:-

Stationary wave is produced by the superposition of incident and reflected waves and the speed of stationary wave is the speed of anyone of the incident or reflected wav.

(As given in marking scheme of CIE).
 
Thanx that's perfect! Its exactly what I need as I am writing CIE
 

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