Hi all

wanted to ask following questions, just out of curiosity:

About visible light being electromagnetic radiation:
1. since visible light is essentially electromagnetic radiation, has
any experiments been made to take, let's say radiowaves, and increase
the frequency to make visible light?

2. since visible light has a magnetic component to it, has any
experiments been made to see if this can be used to direct the light
with the help of an external magnetic field (for e.g. creating
holograms or invisibility without metamaterials)?

About using the magnetic component of an electromagnetic field to
transfer power:
3. I remember reading somewhere that the magnetic component does not
propagate through the space between the sending and the receiving
units. In other words that there is no wave between the sender and the
receiver as there would be with the electric component does (such as
in case of a radio wave). The question I have about this is whether
this means that the transfer of the magnetic component can be
considered "superluminal"?

thanks in advance,

JJ

On Wed, 08 Aug 2007 21:12:27 -0700, jjoensuu <j_joensuu@yahoo.com>
wrote:

>Hi all
>
>wanted to ask following questions, just out of curiosity:
>
>About visible light being electromagnetic radiation:
>1. since visible light is essentially electromagnetic radiation, has
>any experiments been made to take, let's say radiowaves, and increase
>the frequency to make visible light?

Infrared can be multiplied (through nonlinear crystals and such) into
visible or UV, but I've never heard of a way to multiply RF the
millions of times necessary to become visible light.

>
>2. since visible light has a magnetic component to it, has any
>experiments been made to see if this can be used to direct the light
>with the help of an external magnetic field (for e.g. creating
>holograms or invisibility without metamaterials)?

Magnetic fields do not deflect electromagnetic radiation.


>
>About using the magnetic component of an electromagnetic field to
>transfer power:
>3. I remember reading somewhere that the magnetic component does not
>propagate through the space between the sending and the receiving
>units. In other words that there is no wave between the sender and the
>receiver as there would be with the electric component does (such as
>in case of a radio wave). The question I have about this is whether
>this means that the transfer of the magnetic component can be
>considered "superluminal"?

An electromagnetic wave does indeed have real electric and magnetic
components. They reinforce one another and travel together at the
speed of light. Both components can be measured.

Light waves and radio waves are the same thing, just with different
frequency/wavelength. Both are quantized.

John

On Wed, 08 Aug 2007 21:12:27 -0700, jjoensuu wrote:

> Hi all
>
> wanted to ask following questions, just out of curiosity:
>
> About visible light being electromagnetic radiation:
> 1. since visible light is essentially electromagnetic radiation, has
> any experiments been made to take, let's say radiowaves, and increase
> the frequency to make visible light?

That would be very difficult. But some of the higher-frequency microwaves
in the cosmic microwave background were visible red light at the time they
were emitted.

> 2. since visible light has a magnetic component to it, has any
> experiments been made to see if this can be used to direct the light
> with the help of an external magnetic field (for e.g. creating
> holograms or invisibility without metamaterials)?

When two electromagnetic fields are in the same place, they just add
together. They don't affect each other in any other way. So you couldn't
bend light with magnets.

There are certain materials in which the above does not hold. Of course,
in those cases, it's really the magnetic field affecting the material, in
turn affecting the light, rather than a direct effect.

> About using the magnetic component of an electromagnetic field to
> transfer power:
> 3. I remember reading somewhere that the magnetic component does not
> propagate through the space between the sending and the receiving
> units. In other words that there is no wave between the sender and the
> receiver as there would be with the electric component does (such as
> in case of a radio wave). The question I have about this is whether
> this means that the transfer of the magnetic component can be
> considered "superluminal"?

I doubt it. Probably they meant that the magnetic field is either a
standing wave or a static field, but it's hard to tell what they meant by
that description.

--
Jim E. Black

jimp@specsol.spam.sux.com wrote:

> In sci.physics jjoensuu <j_joensuu@yahoo.com> wrote:
> > Hi all
>
> > wanted to ask following questions, just out of curiosity:
>
> > About visible light being electromagnetic radiation:
> > 1. since visible light is essentially electromagnetic radiation, has
> > any experiments been made to take, let's say radiowaves, and increase
> > the frequency to make visible light?
>
> Light is not "essentially electromagnetic radiation".
>
> Light is electromagnetic radiation.
>
> How do you increase the frequency of "radiowaves"?
>
> > 2. since visible light has a magnetic component to it, has any
> > experiments been made to see if this can be used to direct the light
> > with the help of an external magnetic field (for e.g. creating
> > holograms or invisibility without metamaterials)?
>
> > About using the magnetic component of an electromagnetic field to
> > transfer power:
> > 3. I remember reading somewhere that the magnetic component does not
> > propagate through the space between the sending and the receiving
> > units. In other words that there is no wave between the sender and the
> > receiver as there would be with the electric component does (such as
> > in case of a radio wave). The question I have about this is whether
> > this means that the transfer of the magnetic component can be
> > considered "superluminal"?
>
> > thanks in advance,
>
> See above.
>
> I would highly suggest reading up on electromagnetic radiation before
> asking any more questions as you current questions show zero understanding.

Reminiscent of a radium post.

Graham

jjoensuu wrote:
> Hi all
>
> wanted to ask following questions, just out of curiosity:
>
> About visible light being electromagnetic radiation:
> 1. since visible light is essentially electromagnetic radiation, has
> any experiments been made to take, let's say radiowaves, and increase
> the frequency to make visible light?

Yes, nonlinear processes allow for second, third, fourth.... harmonic
generation. For example, it's fairly common for the 1064 nm output for a
Nd:YAG laser to be doubled to green (532nm), or quadrupled to 266 nm. I
think the record is 33rd harmonic generation.

Radio has wavelengths in the cm range (IIRC), so you would be talking
multiple harmonic generation to reach the visible, and I don't know if
there are obvious materials that respond appropriately in the radio range.

> 2. since visible light has a magnetic component to it, has any
> experiments been made to see if this can be used to direct the light
> with the help of an external magnetic field (for e.g. creating
> holograms or invisibility without metamaterials)?

For linear media, there is no interaction between an external
electrostatic, magnetostatic, or electromagnetic field with a given
electromagnetic field. You require nonlinear materials (which exist)
and large magnetostatic fields.

>
> About using the magnetic component of an electromagnetic field to
> transfer power:
> 3. I remember reading somewhere that the magnetic component does not
> propagate through the space between the sending and the receiving
> units. In other words that there is no wave between the sender and the
> receiver as there would be with the electric component does (such as
> in case of a radio wave). The question I have about this is whether
> this means that the transfer of the magnetic component can be
> considered "superluminal"?

Can you provide a reference? This does not make sense. Some of the new
wireless power transfer ideas involve evanescent fields, which are quite
different prom propogating fields.

--
Andrew Resnick, Ph.D.
Department of Physiology and Biophysics
Case Western Reserve University

Circa Thu, 09 Aug 2007 04:34:59 GMT recorded as
<ethqo4-7o.ln1@mail.specsol.com> looks like jimp@specsol.spam.sux.com
sounds like:

>
>I would highly suggest reading up on electromagnetic radiation before
>asking any more questions as you current questions show zero understanding.

Hi there. I try not to be the preachy type, but I hope you would have
noticed that you crossposted this reply to sci.electronics.basics. That
group is rather specialized in that it is devoted to answering questions
posed by those with little knowledge of the field, hence "basics."

At any level, however, I fail to see any gain in a response that,
paraphrasing, says, "You don't know the answer, so don't ask the question."
Telling is the fact that while others considered the posted question and
gave good answers, you only criticized the poster. What's the point of
that, unless to mask ignorance on your own part?

On 9 ao=FBt, 00:12, jjoensuu <j_joen...@yahoo.com> wrote:
> Hi all
>
> wanted to ask following questions, just out of curiosity:
>
> About visible light being electromagnetic radiation:
> 1. since visible light is essentially electromagnetic radiation,

If you remove the "essentially", you have it right.

> has any experiments been made to take, let's say radiowaves,
> and increase the frequency to make visible light?

No real use for such an experiment. Simply for the fact that
radio waves travel at c just like light is sufficient to confirm
identity in nature.

> 2. since visible light has a magnetic component to it, has any
> experiments been made to see if this can be used to direct the light
> with the help of an external magnetic field (for e.g. creating
> holograms or invisibility without metamaterials)?

There are problems with verifying such a thing. The first is that
despite Maxwell's perfect description of electromagnetic energy
at the general level, some many still think in the community that
electromagnetic energy can have no electric nor magnetic
component. Interesting no ?

Second, we know since Planck/ Einstein that light is in fact
made up of myriads of localized photons traveling at c, each
one coming into being as electrons move to lower energy
states in atoms. This means their individual electric and
magnetic components of such small quanta will be close
to infinitesimal in intensity.

The speed is the major hindrance for observing possible light
deflection with magnets since the technological level to
reach the intensities required to deflect the trajectory of
anything moving at c that has no mass in a manner that
can be measured has not been reached yet.

We know however since Faraday that magnetic fields can
affect the polarity of light subjected to magnetic fields.
This observation by Faraday is in fact what started Maxwell
thinking in the mid 1800's and caused him 26 years later to
come up with his final theory.

> About using the magnetic component of an electromagnetic field to
> transfer power:
> 3. I remember reading somewhere that the magnetic component does not
> propagate through the space between the sending and the receiving
> units.

Yes. All magnetic fields seem to act only locally.

> In other words that there is no wave between the sender and the
> receiver as there would be with the electric component does (such as
> in case of a radio wave). The question I have about this is whether
> this means that the transfer of the magnetic component can be
> considered "superluminal"?

Not likely.

You would gain much understanding by reading some intro undergrad
reference, such as Halliday & Resnick, Sears Zemansky and Young,
or any other intro undergrad ref.

Andr=E9 Michaud

On Wed, 08 Aug 2007 21:42:23 -0700, John Larkin wrote:
> ...
> An electromagnetic wave does indeed have real electric and magnetic
> components. They reinforce one another and travel together at the
> speed of light. Both components can be measured.
>
> Light waves and radio waves are the same thing, just with different
> frequency/wavelength. Both are quantized.

This "quantized" stuff really bothered me when I was first into ham radio -
I just couldn't visualize an individual photon 40 meters long!

Thanks!
Rich

On 8/9/07 6:15 AM, in article de4mb3paprcu0m6qhfa8s8q3aq6vm0ikt9@4ax.com,
"Charlie Siegrist" <chamarsie.spam@spam.cableone.net> wrote:

> Circa Thu, 09 Aug 2007 04:34:59 GMT recorded as
> <ethqo4-7o.ln1@mail.specsol.com> looks like jimp@specsol.spam.sux.com
> sounds like:
>
>>
>> I would highly suggest reading up on electromagnetic radiation before
>> asking any more questions as you current questions show zero understanding.
>
> Hi there. I try not to be the preachy type, but I hope you would have
> noticed that you crossposted this reply to sci.electronics.basics. That
> group is rather specialized in that it is devoted to answering questions
> posed by those with little knowledge of the field, hence "basics."
>
> At any level, however, I fail to see any gain in a response that,
> paraphrasing, says, "You don't know the answer, so don't ask the question."
> Telling is the fact that while others considered the posted question and
> gave good answers, you only criticized the poster. What's the point of
> that, unless to mask ignorance on your own part?
>

I agree with the poster you quoted. Posting to a newsboard should not be a
first effort. The first effort should be some personal effort by way of
reading, Google searches, etc.

Your post is, in part, a flame based on your *assumption* that his point was
anything other than to redirect the OP with some good advice. You are
ignorant of his knowledge in the subject area.

On Thu, 09 Aug 2007 13:45:06 -0700, in message
<C2E0CAE2.72D25%dbowey@comcast.net>, Don Bowey <dbowey@comcast.net>
scribed:

>
>I agree with the poster you quoted. Posting to a newsboard should not be a
>first effort. The first effort should be some personal effort by way of
>reading, Google searches, etc.
>
>Your post is, in part, a flame based on your *assumption* that his point was
>anything other than to redirect the OP with some good advice. You are
>ignorant of his knowledge in the subject area.

And I will continue to disagree with both points of view presented to me in
reply. Had the OP not posed the question, the several excellent replies
would never had been made. Those answers immediately remove the question
from the "stupid question" category, and have improved the reading of the
newsgroup. Sorry, this is a "basics" newsgroup, and any on-topic and
sincere question should be welcome without undue criticism.

On Thu, 09 Aug 2007 18:07:53 GMT, Rich Grise <rich@example.net> wrote:

>On Wed, 08 Aug 2007 21:42:23 -0700, John Larkin wrote:
>> ...
>> An electromagnetic wave does indeed have real electric and magnetic
>> components. They reinforce one another and travel together at the
>> speed of light. Both components can be measured.
>>
>> Light waves and radio waves are the same thing, just with different
>> frequency/wavelength. Both are quantized.
>
>This "quantized" stuff really bothered me when I was first into ham radio -
>I just couldn't visualize an individual photon 40 meters long!
>
>Thanks!
>Rich

I figure that a 1-watt, 1 MHz transmitter sprays out about 1.5e27
photons per second, and they are each (fuzzily) about 300 meters long.

John

On Thu, 09 Aug 2007 17:32:14 -0700, John Larkin
<jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:

>On Thu, 09 Aug 2007 18:07:53 GMT, Rich Grise <rich@example.net> wrote:
>
>>On Wed, 08 Aug 2007 21:42:23 -0700, John Larkin wrote:
>>> ...
>>> An electromagnetic wave does indeed have real electric and magnetic
>>> components. They reinforce one another and travel together at the
>>> speed of light. Both components can be measured.
>>>
>>> Light waves and radio waves are the same thing, just with different
>>> frequency/wavelength. Both are quantized.
>>
>>This "quantized" stuff really bothered me when I was first into ham radio -
>>I just couldn't visualize an individual photon 40 meters long!
>>
>>Thanks!
>>Rich
>
>I figure that a 1-watt, 1 MHz transmitter sprays out about 1.5e27
>photons per second, and they are each (fuzzily) about 300 meters long.

I drive through a tunnel on my commute. Early on, I noticed that I
could get an FM station all the way through the tunnel, but I couldn't
pick up any AM stations. I told myself it was because the photons
couldn't fit into the tunnel.

--
Al in St. Lou

On Thu, 09 Aug 2007 20:29:13 -0500, Al in Dallas
<alfargnoli@yahoo.com> wrote:

>On Thu, 09 Aug 2007 17:32:14 -0700, John Larkin
><jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:
>
>>On Thu, 09 Aug 2007 18:07:53 GMT, Rich Grise <rich@example.net> wrote:
>>
>>>On Wed, 08 Aug 2007 21:42:23 -0700, John Larkin wrote:
>>>> ...
>>>> An electromagnetic wave does indeed have real electric and magnetic
>>>> components. They reinforce one another and travel together at the
>>>> speed of light. Both components can be measured.
>>>>
>>>> Light waves and radio waves are the same thing, just with different
>>>> frequency/wavelength. Both are quantized.
>>>
>>>This "quantized" stuff really bothered me when I was first into ham radio -
>>>I just couldn't visualize an individual photon 40 meters long!
>>>
>>>Thanks!
>>>Rich
>>
>>I figure that a 1-watt, 1 MHz transmitter sprays out about 1.5e27
>>photons per second, and they are each (fuzzily) about 300 meters long.
>
>I drive through a tunnel on my commute. Early on, I noticed that I
>could get an FM station all the way through the tunnel, but I couldn't
>pick up any AM stations. I told myself it was because the photons
>couldn't fit into the tunnel.

Exactly.

John

On Thu, 09 Aug 2007 17:32:14 -0700, John Larkin wrote:
> On Thu, 09 Aug 2007 18:07:53 GMT, Rich Grise <rich@example.net> wrote:
>>On Wed, 08 Aug 2007 21:42:23 -0700, John Larkin wrote:
>>> ...
>>> An electromagnetic wave does indeed have real electric and magnetic
>>> components. They reinforce one another and travel together at the
>>> speed of light. Both components can be measured.
>>>
>>> Light waves and radio waves are the same thing, just with different
>>> frequency/wavelength. Both are quantized.
>>
>>This "quantized" stuff really bothered me when I was first into ham radio -
>>I just couldn't visualize an individual photon 40 meters long!
>
> I figure that a 1-watt, 1 MHz transmitter sprays out about 1.5e27
> photons per second, and they are each (fuzzily) about 300 meters long.

Yeah - right after I posted this, I realized - it shouldn't be too hard
to capture these photons, since there are so many.

But where do you get 1.5e27? I'd think a 1-MHz transmitter would only
send out 1,000,000 photons per second. Aren't "photon" and "wave" almost
interchangeable at the quantum level?

Thanks,
Rich

On Thu, 09 Aug 2007 20:29:13 -0500, Al in Dallas wrote:
> On Thu, 09 Aug 2007 17:32:14 -0700, John Larkin
>>On Thu, 09 Aug 2007 18:07:53 GMT, Rich Grise <rich@example.net> wrote:
>>>On Wed, 08 Aug 2007 21:42:23 -0700, John Larkin wrote:
>>>> ...
>>>> An electromagnetic wave does indeed have real electric and magnetic
>>>> components. They reinforce one another and travel together at the
>>>> speed of light. Both components can be measured.
>>>>
>>>> Light waves and radio waves are the same thing, just with different
>>>> frequency/wavelength. Both are quantized.
>>>
>>>This "quantized" stuff really bothered me when I was first into ham radio -
>>>I just couldn't visualize an individual photon 40 meters long!
>>
>>I figure that a 1-watt, 1 MHz transmitter sprays out about 1.5e27
>>photons per second, and they are each (fuzzily) about 300 meters long.
>
> I drive through a tunnel on my commute. Early on, I noticed that I
> could get an FM station all the way through the tunnel, but I couldn't
> pick up any AM stations. I told myself it was because the photons
> couldn't fit into the tunnel.

I once had a pick-up at a little industrial/office/warehouse complex,
that had a broadcast transmitter and antenna array on top of it. It was
kind of weird - drive into the complex, just like going into any little
industrial park, but there was a grid of wires from rooftop to rooftop,
which clearly shielded the underneath from the RF, because my car radio
didn't get disrupted at all.

Cheers!
Rich

"Rich Grise" <rich@example.net> wrote in message
news:pan.2007.08.11.01.44.12.632028@example.net...
> But where do you get 1.5e27? I'd think a 1-MHz transmitter would only
> send out 1,000,000 photons per second. Aren't "photon" and "wave" almost
> interchangeable at the quantum level?

Think about it - this is where the "1 watt" specification comes in.
A single quantum of light - which is what a photon is - carries a
specific amount of energy, depending on the frequency of the
light in question.\

Or another way to look at it - suppose I have a light on a dimmer.
I start with the light dim and then turn it up. What changed, in
terms of "photons"?

Bob M.

On Sat, 11 Aug 2007 01:42:46 GMT, Rich Grise <rich@example.net> wrote:

>On Thu, 09 Aug 2007 17:32:14 -0700, John Larkin wrote:
>> On Thu, 09 Aug 2007 18:07:53 GMT, Rich Grise <rich@example.net> wrote:
>>>On Wed, 08 Aug 2007 21:42:23 -0700, John Larkin wrote:
>>>> ...
>>>> An electromagnetic wave does indeed have real electric and magnetic
>>>> components. They reinforce one another and travel together at the
>>>> speed of light. Both components can be measured.
>>>>
>>>> Light waves and radio waves are the same thing, just with different
>>>> frequency/wavelength. Both are quantized.
>>>
>>>This "quantized" stuff really bothered me when I was first into ham radio -
>>>I just couldn't visualize an individual photon 40 meters long!
>>
>> I figure that a 1-watt, 1 MHz transmitter sprays out about 1.5e27
>> photons per second, and they are each (fuzzily) about 300 meters long.
>
>Yeah - right after I posted this, I realized - it shouldn't be too hard
>to capture these photons, since there are so many.
>
>But where do you get 1.5e27? I'd think a 1-MHz transmitter would only
>send out 1,000,000 photons per second. Aren't "photon" and "wave" almost
>interchangeable at the quantum level?
>
>Thanks,
>Rich


Each radio "wave" is a heap of quanta piled on top one another. The
higher the transmitter power, the more quanta in each wave.

Each quantum carries a tiny amount of energy.

http://en.wikipedia.org/wiki/Planck%27s_constant

A 1 MHz quantum carries about 1e6 * h joules, or about 6.6 e-28
joules.

John

On Thu, 09 Aug 2007 19:53:29 -0700, John Larkin
<jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:

>On Thu, 09 Aug 2007 20:29:13 -0500, Al in Dallas
><alfargnoli@yahoo.com> wrote:
>
>>On Thu, 09 Aug 2007 17:32:14 -0700, John Larkin
>><jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:
>>
>>>On Thu, 09 Aug 2007 18:07:53 GMT, Rich Grise <rich@example.net> wrote:
>>>
>>>>On Wed, 08 Aug 2007 21:42:23 -0700, John Larkin wrote:
>>>>> ...
>>>>> An electromagnetic wave does indeed have real electric and magnetic
>>>>> components. They reinforce one another and travel together at the
>>>>> speed of light. Both components can be measured.
>>>>>
>>>>> Light waves and radio waves are the same thing, just with different
>>>>> frequency/wavelength. Both are quantized.
>>>>
>>>>This "quantized" stuff really bothered me when I was first into ham radio -
>>>>I just couldn't visualize an individual photon 40 meters long!
>>>>
>>>>Thanks!
>>>>Rich
>>>
>>>I figure that a 1-watt, 1 MHz transmitter sprays out about 1.5e27
>>>photons per second, and they are each (fuzzily) about 300 meters long.
>>
>>I drive through a tunnel on my commute. Early on, I noticed that I
>>could get an FM station all the way through the tunnel, but I couldn't
>>pick up any AM stations. I told myself it was because the photons
>>couldn't fit into the tunnel.
>
>Exactly.

Hmmm, that leaves me imagining the photons as huge invisible spheres.
Is there really severe attenuation when the slits in a double-slit
experiment get smaller than a wavelength? If not, the "not fitting"
wouild seem to be a poor heuristic.

--
Al in St. Lou

On Sat, 11 Aug 2007 01:47:08 GMT, Rich Grise <rich@example.net> wrote:

>On Thu, 09 Aug 2007 20:29:13 -0500, Al in Dallas wrote:
>> On Thu, 09 Aug 2007 17:32:14 -0700, John Larkin
>>>On Thu, 09 Aug 2007 18:07:53 GMT, Rich Grise <rich@example.net> wrote:
>>>>On Wed, 08 Aug 2007 21:42:23 -0700, John Larkin wrote:
>>>>> ...
>>>>> An electromagnetic wave does indeed have real electric and magnetic
>>>>> components. They reinforce one another and travel together at the
>>>>> speed of light. Both components can be measured.
>>>>>
>>>>> Light waves and radio waves are the same thing, just with different
>>>>> frequency/wavelength. Both are quantized.
>>>>
>>>>This "quantized" stuff really bothered me when I was first into ham radio -
>>>>I just couldn't visualize an individual photon 40 meters long!
>>>
>>>I figure that a 1-watt, 1 MHz transmitter sprays out about 1.5e27
>>>photons per second, and they are each (fuzzily) about 300 meters long.
>>
>> I drive through a tunnel on my commute. Early on, I noticed that I
>> could get an FM station all the way through the tunnel, but I couldn't
>> pick up any AM stations. I told myself it was because the photons
>> couldn't fit into the tunnel.
>
>I once had a pick-up at a little industrial/office/warehouse complex,
>that had a broadcast transmitter and antenna array on top of it. It was
>kind of weird - drive into the complex, just like going into any little
>industrial park, but there was a grid of wires from rooftop to rooftop,
>which clearly shielded the underneath from the RF, because my car radio
>didn't get disrupted at all.

When I worked in telecom, and they wanted to shield up to 1.9 GHz,
they used shielded rooms (from Lindgren!) which had screens with a
fine enough mesh that the A/C didn't seem to penetrate, but we could
see through. Before that, I worked in defense where our shielded rooms
had solid walls, but we were interested in significantly higher
frequencies. (If I told you, I'd have to kill you

--
Al in St. Lou

On Fri, 10 Aug 2007 23:43:43 -0500, Al in Dallas
<alfargnoli@yahoo.com> wrote:

>On Thu, 09 Aug 2007 19:53:29 -0700, John Larkin
><jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:
>
>>On Thu, 09 Aug 2007 20:29:13 -0500, Al in Dallas
>><alfargnoli@yahoo.com> wrote:
>>
>>>On Thu, 09 Aug 2007 17:32:14 -0700, John Larkin
>>><jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:
>>>
>>>>On Thu, 09 Aug 2007 18:07:53 GMT, Rich Grise <rich@example.net> wrote:
>>>>
>>>>>On Wed, 08 Aug 2007 21:42:23 -0700, John Larkin wrote:
>>>>>> ...
>>>>>> An electromagnetic wave does indeed have real electric and magnetic
>>>>>> components. They reinforce one another and travel together at the
>>>>>> speed of light. Both components can be measured.
>>>>>>
>>>>>> Light waves and radio waves are the same thing, just with different
>>>>>> frequency/wavelength. Both are quantized.
>>>>>
>>>>>This "quantized" stuff really bothered me when I was first into ham radio -
>>>>>I just couldn't visualize an individual photon 40 meters long!
>>>>>
>>>>>Thanks!
>>>>>Rich
>>>>
>>>>I figure that a 1-watt, 1 MHz transmitter sprays out about 1.5e27
>>>>photons per second, and they are each (fuzzily) about 300 meters long.
>>>
>>>I drive through a tunnel on my commute. Early on, I noticed that I
>>>could get an FM station all the way through the tunnel, but I couldn't
>>>pick up any AM stations. I told myself it was because the photons
>>>couldn't fit into the tunnel.
>>
>>Exactly.
>
>Hmmm, that leaves me imagining the photons as huge invisible spheres.

They must have an interesting 3D shape in space, sort of a fuzzy ball
but with bands or shells of density, tapering off with distance from
the center. Maybe somebody in one of the physics groups could furnish
a link to some E/H field density maps that visualize the "shape" of a
photon.

Something like this?

http://superstruny.aspweb.cz/images/fyzika/foton.gif



>Is there really severe attenuation when the slits in a double-slit
>experiment get smaller than a wavelength? If not, the "not fitting"
>wouild seem to be a poor heuristic.

Yup, as an opening (or a tunnel/waveguide) gets smaller, the
probability of a photon getting through drops radically. But being a
photon, either it all bounces off or it all squeezes through.

Somebody said that if quantum mechanics doesn't frighten you, you
haven't studied it enough.

John

On Aug 9, 12:12 am, jjoensuu <j_joen...@yahoo.com> wrote:
> Hi all
>
> wanted to ask following questions, just out of curiosity:
>
> About visible light being electromagnetic radiation:
> 1. since visible light is essentially electromagnetic radiation, has
> any experiments been made to take, let's say radiowaves, and increase
> the frequency to make visible light?
>

Something similar. Visible or near-IR laser beams have been converted
into x-rays beams.

If you could make a mirror that moves near the speed of light, there
would be a very large increase or decrease in a reflected EM wave's
wavelength, depending on whether the mirror is moving toward or away
from the beam.

Compton scattering off of relativistic electrons in an accelerator is,
essentially, EM waves scattering from mirrors moving near light
speed. I first heard of it being done in the mid or late 1990's.

For example see (especially the last abstract):
http://www.camd.lsu.edu/SRI/Workshop3.pdf

Regards,

Mark

On Sat, 11 Aug 2007 09:02:06 -0700, John Larkin
<jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:

>On Fri, 10 Aug 2007 23:43:43 -0500, Al in Dallas
><alfargnoli@yahoo.com> wrote:
>
>>On Thu, 09 Aug 2007 19:53:29 -0700, John Larkin
>><jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:
>>
>>>On Thu, 09 Aug 2007 20:29:13 -0500, Al in Dallas
>>><alfargnoli@yahoo.com> wrote:
>>>
>>>>On Thu, 09 Aug 2007 17:32:14 -0700, John Larkin
>>>><jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:
>>>>
>>>>>On Thu, 09 Aug 2007 18:07:53 GMT, Rich Grise <rich@example.net> wrote:
>>>>>
>>>>>>On Wed, 08 Aug 2007 21:42:23 -0700, John Larkin wrote:
>>>>>>> ...
>>>>>>> An electromagnetic wave does indeed have real electric and magnetic
>>>>>>> components. They reinforce one another and travel together at the
>>>>>>> speed of light. Both components can be measured.
>>>>>>>
>>>>>>> Light waves and radio waves are the same thing, just with different
>>>>>>> frequency/wavelength. Both are quantized.
>>>>>>
>>>>>>This "quantized" stuff really bothered me when I was first into ham radio -
>>>>>>I just couldn't visualize an individual photon 40 meters long!
>>>>>>
>>>>>>Thanks!
>>>>>>Rich
>>>>>
>>>>>I figure that a 1-watt, 1 MHz transmitter sprays out about 1.5e27
>>>>>photons per second, and they are each (fuzzily) about 300 meters long.
>>>>
>>>>I drive through a tunnel on my commute. Early on, I noticed that I
>>>>could get an FM station all the way through the tunnel, but I couldn't
>>>>pick up any AM stations. I told myself it was because the photons
>>>>couldn't fit into the tunnel.
>>>
>>>Exactly.
>>
>>Hmmm, that leaves me imagining the photons as huge invisible spheres.
>
>They must have an interesting 3D shape in space, sort of a fuzzy ball
>but with bands or shells of density, tapering off with distance from
>the center. Maybe somebody in one of the physics groups could furnish
>a link to some E/H field density maps that visualize the "shape" of a
>photon.
>
>Something like this?
>
>http://superstruny.aspweb.cz/images/fyzika/foton.gif

Wow, that really does look like a chunk of a field.

>>Is there really severe attenuation when the slits in a double-slit
>>experiment get smaller than a wavelength? If not, the "not fitting"
>>wouild seem to be a poor heuristic.
>
>Yup, as an opening (or a tunnel/waveguide) gets smaller, the
>probability of a photon getting through drops radically. But being a
>photon, either it all bounces off or it all squeezes through.
>
>Somebody said that if quantum mechanics doesn't frighten you, you
>haven't studied it enough.

I thought Feynman said something along the lines of if you don't see a
problem understanding quantum mechanics, you don't understand it at
all.

--
Al in St. Lou

On Fri, 10 Aug 2007 21:22:42 -0700, John Larkin wrote:
> On Sat, 11 Aug 2007 01:42:46 GMT, Rich Grise <rich@example.net> wrote:
>>On Thu, 09 Aug 2007 17:32:14 -0700, John Larkin wrote:
>>> On Thu, 09 Aug 2007 18:07:53 GMT, Rich Grise <rich@example.net> wrote:
>>>>On Wed, 08 Aug 2007 21:42:23 -0700, John Larkin wrote:
>>>>> ...
>>>>> An electromagnetic wave does indeed have real electric and magnetic
>>>>> components. They reinforce one another and travel together at the
>>>>> speed of light. Both components can be measured.
>>>>>
>>>>> Light waves and radio waves are the same thing, just with different
>>>>> frequency/wavelength. Both are quantized.
>>>>
>>>>This "quantized" stuff really bothered me when I was first into ham radio -
>>>>I just couldn't visualize an individual photon 40 meters long!
>>>
>>> I figure that a 1-watt, 1 MHz transmitter sprays out about 1.5e27
>>> photons per second, and they are each (fuzzily) about 300 meters long.
>>
>>Yeah - right after I posted this, I realized - it shouldn't be too hard
>>to capture these photons, since there are so many.
>>
>>But where do you get 1.5e27? I'd think a 1-MHz transmitter would only
>>send out 1,000,000 photons per second. Aren't "photon" and "wave" almost
>>interchangeable at the quantum level?
>
> Each radio "wave" is a heap of quanta piled on top one another. The
> higher the transmitter power, the more quanta in each wave.
>
> Each quantum carries a tiny amount of energy.
>
> http://en.wikipedia.org/wiki/Planck%27s_constant
>
> A 1 MHz quantum carries about 1e6 * h joules, or about 6.6 e-28
> joules.

Ah, I get it now. I guess I've "seen the light". Thanks.

Cheers!
Rich

On Thu, 16 Aug 2007 10:17:30 +0100, "Anonymous." <me@privacy.net>
wrote:

>"Rich Grise" <rich@example.net> wrote in message
>news:pan.2007.08.16.00.35.05.220029@example.net...
>> On Fri, 10 Aug 2007 21:22:42 -0700, John Larkin wrote:
>>> On Sat, 11 Aug 2007 01:42:46 GMT, Rich Grise <rich@example.net> wrote:
>>>>On Thu, 09 Aug 2007 17:32:14 -0700, John Larkin wrote:
>>>>> On Thu, 09 Aug 2007 18:07:53 GMT, Rich Grise <rich@example.net> wrote:
>>>>>>On Wed, 08 Aug 2007 21:42:23 -0700, John Larkin wrote:
>>>>>>> ...
>>>>>>> An electromagnetic wave does indeed have real electric and magnetic
>>>>>>> components. They reinforce one another and travel together at the
>>>>>>> speed of light. Both components can be measured.
>>>>>>>
>>>>>>> Light waves and radio waves are the same thing, just with different
>>>>>>> frequency/wavelength. Both are quantized.
>>>>>>
>>>>>>This "quantized" stuff really bothered me when I was first into ham
>>>>>>radio -
>>>>>>I just couldn't visualize an individual photon 40 meters long!
>>>>>
>>>>> I figure that a 1-watt, 1 MHz transmitter sprays out about 1.5e27
>>>>> photons per second, and they are each (fuzzily) about 300 meters long.
>
>I've missed this thread somehow.
>
>Quantised effects apply when radiation comes from intra-atom
>effects and is limited to a number of fixed levels.

There are non-atomic ways to make EM radiation, like deflecting an
electron by a magnetic field. Each generated quantum has a distinct
energy/wavelength, but any wavelength can be generated by varying the
parameters; there are no discrete levels here, as there are in an
atom. A free-electron laser is continuously tunable.


>
>RF radiation in general* is not limited to such fixed levels and can occur
>at any frequency.
>
>Rf radiation in general* depends upon macro current phenomena and not
>intra-atomic phenomena.
>
>*masers at the frequencies of intra-atomic effects possibly excepted.
>

All electromagnetic radiation is the same. It's all quantized. The
only difference between AM radio quanta and gamma rays is the
wavelength and corresponding energy of the photons.

John

Anonymous. wrote:
> "John Larkin" <jjlarkin@highNOTlandTHIStechnologyPART.com> wrote in message
> news:nir8c3hcagq7rcnilfshorqqmrhpq0mhl7@4ax.com...
>
>>All electromagnetic radiation is the same. It's all quantized.
>
>
> Is there any experimental evidence for that?

Cavity QED experiments performed using microwaves, among other experiments.

--
Andrew Resnick, Ph.D.
Department of Physiology and Biophysics
Case Western Reserve University