Re: Argument of wavefunction

[Bob Sciamanda <trebor@VELOCITY.NET>]

Sarma,
If you do it carefully, both function forms will show the same result. Be
aware that eg. at t=0 and x=0 sin(kx-wt) is going negative while
sin(wt-kx) is going positive.

Bob Sciamanda (W3NLV)
Physics, Edinboro Univ of PA (em)
trebor@velocity.net
http://www.velocity.net/~trebor
----- Original Message -----
From: "D.V.N.Sarma" <narayana@HD1.VSNL.NET.IN>
To: <PHYS-L@lists.nau.edu>
Sent: Wednesday, February 27, 2002 12:52 AM
Subject: Argument of wavefunction


> Here is question concerning pedagogy.
>
> While teaching reflection of waves at boundaries some books
> use sin(kx-wt) as the argument and some use sin(wt-kx) as the
> wave function. If we use sin(wt-kx) we get the amplitude of the
> reflected wave A(R)=(k1-k2)A(I)/(k1+k2) where ks are the
> propagation constants. If k2>k1 this equation automatically
> tells you that A(R) has opposite sign to that of A(I) the incident
> amplitude. This I think is preferable because it allows the student
> to understand the phase change of the reflected wave from the
> boundary of medium of greater impedance. If we take sin(kx-wt)
> this does not come directly.
>
> What are the experiences of the list members regarding this.
>
> regards,
>
> Sarma.