Re: [Phys-l] Amplitude in E&M

[brian whatcott <betwys1@sbcglobal.net>]

On 9/20/2011 5:21 PM, Bill Nettles wrote:
> > -----Original Message-----
> > From: phys-l-bounces@carnot.physics.buffalo.edu [mailto:phys-l-
> > bounces@carnot.physics.buffalo.edu] On Behalf Of Zeke Kossover
> > Sent: Monday, September 19, 2011 3:12 PM
> > To: phys-l@carnot.physics.buffalo.edu
> > Subject: [Phys-l] Amplitude in E&M
> >
> > Two questions
> >
> > 1. Would it be reasonable to say (that is, pedagogically a good idea)
> > that an electromagnetic wave has an amplitude?
> >
> > 2. Why are microwaves reflected by a piece of metal and not gamma rays?
> > Don't both have a skin effect?
> >
> > Thank you.
> [Bill Nettles] Looking at #2, the order of magnitude of the wavelength of a microwave is 1 mm. For a gamma ray, it's 1 pm.  Compare these to the intermolecular or interatomic spacing of the material. What does this tell you about the comparative chance of interaction?
So for a 10 pm gamma and a FCC metal like gold, silver, copper with a 
representative lattice dimension of 250 pm,
the glancing angle for significant interaction would be about  arc tan 
10/250 say 2 degrees then?

Brian W