Undergrad Measuring Wave Speed: Reference Frame Considerations

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The wave equation indicates that the speed of wave propagation, denoted as v, is typically measured from the lab frame in classical physics. In relativity, the context of the wave's propagation can complicate the reference frame, particularly for electromagnetic waves, which have a constant speed in all inertial frames. The discussion raises questions about the appropriateness of the lab frame for measuring wave speed and the implications for different types of waves. It emphasizes that while v can be straightforward in classical contexts, relativity introduces complexities that prevent arbitrary reference frame selection. Understanding these distinctions is crucial for accurately interpreting wave behavior across various physical theories.
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In the wave equation## \frac {\partial^2 \psi} {\partial x^2}=\frac{1}{v^2}\frac{\partial^2 \psi}{\partial t^2}\tag{1}##, v is the speed of the wave propagation.
With respect to which reference frame is this speed measured( in general)?
 
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What is the context of your question, classical physics, relativity or quantum mechanics?
 
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classical physics and relativity
 
What do you think v represents for each one then?
 
jedishrfu said:
What do you think v represents for each one then?
v represents speed of the wave propagation.
For example, if we take wave on a string, then the speed is measured from the lab frame.
But how do we know that the speed should be measured from the lab frame( just by knowing the wave equation)?
And why can't we decide the reference frame in case of electromagnetic waves?
 

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