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Re: Waves and Energy




On Sun, 23 Feb 1997, Ed Schweber wrote:

> David Abineri wrote:
> > 
> > I wonder if I can get help on this question from a high school class.
> > 
> > If two electromagnetic waves interfere destructively, what happens to the
> > energy associated with the waves. I am guessing that on the large scale,
> > in a double slit experiment that additional energy shows up at the points
> > of constructive interference that compensates for the loss at the nodes.

That's a correct interpretation. The interference does not cause any
reduction in the total energy in the combined field.

> > But, what about looking as just the waves that are meeting at a node?

Remember that the waves are a mathematical abstraction to describe what we
can measure, in particular, they relate to the probability of finding a
photon at a particular place in space and time. We don't think of the
waves as somehow 'colliding' with each other. 

Ed Schweiber's longer answer put it very well.

        -- Donald

.......................................................................
Dr. Donald E. Simanek                            Office: 717-893-2079
Prof. of Physics                    Internet: dsimanek@eagle.lhup.edu
Lock Haven University, Lock Haven, PA. 17745          CIS: 73147,2166 
Home page: http://www.lhup.edu/~dsimanek            FAX: 717-893-2047
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