Re: [Phys-l] g & E fields

[Brian Whatcott <betwys1@sbcglobal.net>]

At 05:07 AM 1/7/2008, you wrote:
> Quoting Brian Whatcott <betwys1@sbcglobal.net>:
> > At 08:02 PM 12/3/2007, you wrote:
> >> Here is another tricky question on the energy of the electromagnetic
> >> wave: Is the intensity of the bright fringe (For example, Young's
> >> Double Slit Experiment) always the same when the electromagnetic field
> >> is varying? Neither is this question easy to be explained too.
> >>
> >> Alphonsus
> >
> > I'll bite: why is the intensity of a varying sinusoidal wave not
> > instantaneously varying?
>
> Don't bite! This is a very deep question!
>  From the theoretical perspective, the intensity of the em wave is not
> zero when the electric field is zero instantaneously. Why? The
> magnetic field is in its maximum.
>
> Practically speaking, Young Double Slit experiment is also a quantum
> physics problem. For example, if you aim one photon at a time, you may
> not obsserve photons around the "bright finge" instantaneously.
>
> Hence, it is not simply a question of varying sinusoidal
> electromagnetic wave, but quantum wave function or psi wave!
>
>
> Alphonsus

I am doubtless being obtuse by supposing that the rules that
 obtain at low frequencies i.e. for detecting the electric field
of an em wave with a dipole also obtain at light frequencies.
 It boils down to this: how do you wish to define intensity?
If you choose the electric component, your argument fails:
if the electric and magnetic components, your argument
 succeeds.



Brian Whatcott    Altus OK    Eureka!