"V.K.Tamhane" wrote in message
om...
Following paradox was included in my last message, but a poster
advised me to post it separately. He also told me that Dirk Van de
moortel is expert in pin-pointing errors in such things, therefore he
is specially invited.

In my past article, I mentioned what we may
call
an 'absolute phenomenon', which is real only in the frame in which it
occurs. If the results are different in any other frame, these are
apparent results.
If the effects of an event in frame S are different but real in
the
frame S' on account of the velocity of the later, we arrive at a
paradox.
Consider a rectangular coil rotating
between the charged capacitor plates in S, terminals of which are
connected to a low wattage bulb.(by means of slip rings and brushes).
It is known that electric flux cutting action does not produce emf.
Of course the tangential velocities of
the coil sides will see currents in the plates in the vertical
direction. But since the charges are equal and opposite and the
velocities two are equal and opposite, both the coil sides see
currents in the same direction with zero resultant emf. In any case,
magnetic flux would be parallel to the coil sides and so the
direction of the emf would be normal to the length of the coil sides,
again result would be zero emf.
In short, in frame S , the bulb will not
glow. It should however glow as soon as you start 'running' away,
parallel to the plates. As seen in S', there are equal and opposite
currents, which will produce magnetic field in the vertical direction,
which if real must produce emf. Faster you run, brighter the bulb will
glow. Paradox is that, if photon radiation takes place then it should
reach both the frames.

This is actually a classical E&M paradox, which one would _think_
SR has solved, but apparently there is still much confusion on the
subject.

The answer is:

By SR, when an observer runs away, there is
only a magnetic field as seen by the observer running away.
The coil does not see a magnetic field, because there is no
current (additional on the plates) _relative_ to the coil.

The correct classical solution does actually have a
magnetic field of the plates based on its absolute velocity(#),
but the electric field is also altered by the absolute velocity
in such a way that the resulting forces are cancelled.
Thus while the fields are intrinsic properties of the
space, the resulting forces are dependent on relative
velocity only.

# this is like your frame S' running away. But only one
frame S' is the correct frame to determine the current
and velocity contributions to the E&M fields.
One might ask, then how can one ever know what
the electric field is? The answer is we don't (unless
we know what the absolute frame of reference is).
However, if one determines the E&M fields from
any inertial frame, the fields might not be correct,
but any force derived from these fields will be
correct.

H.Ellis Ensle

"Harold Ensle" wrote in message link.net...

[snip]

This is actually a classical E&M paradox, which one would _think_
SR has solved, but apparently there is still much confusion on the
subject.

The answer is:

.... tadaaa.... The dog eats the coil!
http://users.pandora.be/vdmoortel/di...es/WhatIf.html
http://users.pandora.be/vdmoortel/di.../Monopoly.html
http://users.pandora.be/vdmoortel/di...Dissident.html

Dirk Vdm

"Harold Ensle" wrote in message
link.net...

[.......]

This is actually a classical E&M paradox, which one would _think_
SR has solved, but apparently there is still much confusion on the
subject.

No..I was wrong. It is not an E&M paradox since only one frame S'
is allowed. So yes, it is an SR paradox. As to the ultimate contradiction,
SR can get out of it (#)by the following argument, but there still remains
a paradox if one tries to maintain the idea of intrinsic properties
of space.

# They can get out of it, provided that they use real SR and not the
semi-classical view....where there really *is* a contradiction.
It is this semi-classical view that you are using so you can
hardly be faulted for pointing the paradox out (which is correct
for this viewpoint).

The answer is:

By SR, when an observer runs away, there is
only a magnetic field as seen by the observer running away.
The coil does not see a magnetic field, because there is no
current (additional on the plates) _relative_ to the coil.

The correct classical solution does actually have a
magnetic field of the plates based on its absolute velocity(#),
but the electric field is also altered by the absolute velocity
in such a way that the resulting forces are cancelled.
Thus while the fields are intrinsic properties of the
space, the resulting forces are dependent on relative
velocity only.

# this is like your frame S' running away. But only one
frame S' is the correct frame to determine the current
and velocity contributions to the E&M fields.
One might ask, then how can one ever know what
the electric field is? The answer is we don't (unless
we know what the absolute frame of reference is).
However, if one determines the E&M fields from
any inertial frame, the fields might not be correct,
but any force derived from these fields will be
correct.

H.Ellis Ensle

"Harold Ensle" wrote in message hlink.net...

"Harold Ensle" wrote in message
link.net...

[.......]

This is actually a classical E&M paradox, which one would _think_
SR has solved, but apparently there is still much confusion on the
subject.

No..I was wrong. It is not an E&M paradox since only one frame S'
is allowed.

And of course the observer of that frame 'cannot apply
a transformation to himself', can he?
http://users.pandora.be/vdmoortel/di...nnotApply.html

Dirk Vdm

"Dirk Van de moortel" wrote in message ...
"Harold Ensle" wrote in message hlink.net...

"Harold Ensle" wrote in message
link.net...

[.......]

This is actually a classical E&M paradox, which one would _think_
SR has solved, but apparently there is still much confusion on the
subject.

No..I was wrong. It is not an E&M paradox since only one frame S'
is allowed.

And of course the observer of that frame 'cannot apply
a transformation to himself', can he?
http://users.pandora.be/vdmoortel/di...nnotApply.html

So may I know for which frame the magnetic field exists? There is
no difference in the frames. If you like, you can place the apparatus
in the frame S', Now an observer in S must see the photons reaching
him but in reality they will not be produced in the frame S'.
secondly, fumble is better than rote.

Dirk Vdm

"Dirk Van de moortel" wrote
in message ...

"Harold Ensle" wrote in message
hlink.net...

"Harold Ensle" wrote in message
link.net...

[.......]

This is actually a classical E&M paradox, which one would _think_
SR has solved, but apparently there is still much confusion on the
subject.

No..I was wrong. It is not an E&M paradox since only one frame S'
is allowed.

And of course the observer of that frame 'cannot apply
a transformation to himself', can he?

Quite true. After all, his velocity relative to himself is always
zero. I fail to see why you can't understand something so simple.

Dirk Vdm

....I wish someone intelligent would respond to my post.

H.Ellis Ensle

"Harold Ensle" wrote in message news

"Dirk Van de moortel" wrote
in message ...

"Harold Ensle" wrote in message
hlink.net...

"Harold Ensle" wrote in message
link.net...

[.......]

This is actually a classical E&M paradox, which one would _think_
SR has solved, but apparently there is still much confusion on the
subject.

No..I was wrong. It is not an E&M paradox since only one frame S'
is allowed.

And of course the observer of that frame 'cannot apply
a transformation to himself', can he?

Quite true. After all, his velocity relative to himself is always
zero. I fail to see why you can't understand something so simple.

You fail indeed. Miserably.


Dirk Vdm

...I wish someone intelligent would respond to my post.

Your wish has been fulfilled.
Now do something with it.

Dirk Vdm