"Harry" wrote in message
...

"Bilge" wrote in message
...
Harold Ensle:

"Bilge" wrote in message
e-al.net...
V.K.Tamhane:

Taking into consideration that the currents are vectors,

Currents are _NOT_ vectors. Currents are _scalars_. Current
_densities_
are vectors and a current is the surface integral of J,

I = \integral J . dS Note the scalar product.

Whoooo.....this is one of those basic physics errors that worry me.
Current is by definition a vector since it has a direction. (Is the
current going East...west...north..south....up....down...etc)

Wrong. Current is a scalar. Note that ampere's law reads:

curl B = J = \integral (curl B) . dS = \integral J . dS = I

Your equation determines the _magnitude_ of current that passes
throught
the surface. And yes, the _magnitude_ of current is a scalar.

Scalars do not have directions. Note that the bio-savart law reads:
I dl x r, not dI x r.
SNIP

Bilge, indeed for example Alonso&Finn part 2 (Electromagnetism) treats "I"
as only a scalar.

But W.D.Day (Intro to vector analysis for Radio and electronic eng.)
treats
"I" as a vector and writes:
F = I x B (he apparently took l=1).

When a current has one single direction as well as a magnitude it can be
presented as a vector.
Maybe a little sloppy, but very handy!

NO. Current is always a vector by physical definition. It has a
direction therefore it is a vector. ANY equation that yields
a scalar value for a current is, in fact, yielding the magnitude
of the current.

This is not a grey area in physics. This is a basic fundamental
physics definition which if one is not clear about it, one needs
to review.

The fact that people are using various equations to try and
show whether it is a vector or not is completely ridiculous.
An equation does not have to give the vector. It could yield
the magnitude, or just the direction, or just a component...all
depending on the particular equation and its purpose.

H.Ellis Ensle

Faraday told us to look for an underlying cause of the wysiwyg magnetic
field.
Ampere gave us that underlying cause when he described dynamic electrical
fields, (which Faraday could not understand)
Ampere described the product of a bar magnet as having a tangential
electrical field whose sole diffference was direction of field, clockwise as
you view the southseeking pole of a magnet or counter clockwise as you view
the northseeking pole.

Unlike a contiguous leverageable field capable of conveying force as an
action at a distance, a reason for aether,
dynamic electrical fields are avalanch propagated and require no medium.

When a charged particle in motion is painted by a dynamic electrical field
(the kind you are not familiar with) it must recognize that its electrical
environment has changed and will seek a new path of least resistance. This
is "a re-direction of inertia".

If you want to see re-direction of inertia for yourself just hold a bar
magnet up to a crt screen with a cross hatch, and you will see how Ampere's
magnets dynamic electrical field causes a re-direction of inertia to the
electrons in flight inside the crt.

Re-direction of inertia due to a dynamic electrical field is the mechanism
of cause and effect of the magnetic field.
Cause is the motion of the charged particle, and the new electrical
environment, effect is the re-direction of inertia which we percieve as
action at a distance. This doesnot mean the magnetic field (our wysiwys
percieved field doesnt exist, for all practical purpose it does. Especially
for engineering purposes.

While curvature of electrical field supports magnetic response, A gradient
of strength of the spatial charge density supports gravitation as a force
orthogonal to the electrical field and towards the greater spatial charge
density.

In my opinion, Amperes re-direction of inertia is the true GUT. Kind
regards, Lee Pugh


"V.K.Tamhane" wrote in message
m...
Let us first ponder over force acting at a distance. Whenever there
exists such a force between two bodies, the force vector always lies
between them. The bodies, depending on their nature, either attract or
repel in the direction of the line joining them. Force between two
current elements is a bit complex, because sources are vectors and so,
justifiably, we can say that, in this case, the force depends not only
on magnitude but also on the orientation of the sources as well. Hence
for the magnetic force, we have following Biot-Savart law (neglect
constants),

F=(Ia) dot (Ib)/r^2 .........1.

Where Ia and Ib are two parallel current elements in the y
direction, having a distance vector r in the x direction.
This dot product should have been the final word. It is not!
Correct equation is given by following Ampere's law. (Also known as
Ampere's Biot-Savart law),

F= (Ia cross r) cross Ib/r^3 ........2.

(Ia cross r)/r^3 gives magnetic field intensity B. It is in the
z direction. B is not a force vector, because actual force is in the x
direction. (For this reason B is not called force field, it is called
magnetic induction, whatever that may mean).
If we rotate Ib in the y-z plane, then the direction of the
force remains constant in x, always between the elements, but the
magnitude changes from maximum to zero, as Ib changes direction from y
to z respectively.
If we rotate Ib in the x-y plane, then the magnitude of the
force remains constant at maximum but the direction rotates along with
it. Direction of the force is x, when Ib is in the y direction and it
is y when Ib is in the x direction.

And here lies the problem!

If we consider magnetic field just a mathematical entity, same as
electric field, then we must always be able to look at the actual
sources of the force to explain it, Taking into consideration that the
currents are vectors, magnetic force may change in magnitude but never
in the direction. Therefore under all conditions, eq.1 alone should
have been found true. But it is true only as a special case, that when
Ib rotates in the y-z plane.
When the direction of Ib is x, the force exerted on Ib is
parallel to Ia. The force is no more 'between' the current elements
and so no more 'due' to the current elements.
Clearly in the above case, Ib is not responding directly to Ia;
it is responding to the B field of Ia and this is possible only if B
field is real.
Obviously Ib, too, has a real field and the actual mechanical
fore between the current elements is due to the interaction of these
real fields.
The picture of E vector lines is imaginary, which helps
visualization. Picture of circular B lines is not only not imaginary,
but it represents real physical entity. A third entity, after two
others, mass and charge.

Real: such as mass and charge
Intangible: such as force and energy
Fictitious: such as elctric field
-------------------------------------

This is one article out of a serial. New visitors should go through
all the previous. Dates are posting dates. Articles are posted to 1.
Alt.sci.physics.new-theories 2.Sci.physics 3.sci.physics.electromag
4. sci.physics.relativity


1. Limitation of Divergence theorem 8-3-04 1,2,3,4
2. Electron positron annihilation 12-3-04 1,2,3,4
3. Changing magnetic field does
not produce electric field 17-3-04 1,2,3,4
4. Barnett's experiment 22-3-04 1,2,3,4
5. Relativity and electrodynamics 25-3-04 1,2,3,4
6. Relativity of two moving charges 2-4-04 1,2,3,4
7. Relativity of steady charge and current 11-4-04 1,2,3,4
8 Relativity of two currents 14-4-04 1,2,3,4
9. Nature of electric field 16-4-04 1,2,3,4
10. Magnetic field is real 22-4-04 2,3,4
11. once more relativity 5-5-04 1,2,3,4
12. A new paradox in SR 10-5-04 1,2,3,4

Harold Ensle:
"Bilge" wrote in message
ue-al.net...
Harold Ensle, crackpot and idiot,

This is a sign that you know that you are wrong...
you always get more insultive in such cases.
(perhaps you should seek some counseling)

Perhaps you should seek out a physics book.

"V.K.Tamhane" wrote in message
om...
"Harold Ensle" wrote in message
k.net...


Harold sometimes you have to ignore some people. Now that I
have
understood his calibre, I will always ignore him. In the last
message
he said that when the coil loop is linked with maximum flux induced
emf is maximum. In this he proves that he doesn't even know what a
vector is. He says, out of I.dl, I is a scaler and dl is a vector,
when either I or dl can be assigned a direction.

Only if you will allow the existence of a bent vector, such as might
be obtained by nearly straightening a paper clip..

More seriously: The definition of current is that it is the integral
over a surface of the quantity J dot ds, where J is a current density
and ds is a surface element. Both J and ds are vectors. The dot
product is a scalar.

Franz

"Harold Ensle" wrote in message
news

"Franz Heymann" wrote in message
...

"V.K.Tamhane" wrote in message
m...
Let us first ponder over force acting at a distance. Whenever
there
exists such a force between two bodies, the force vector always
lies
between them. The bodies, depending on their nature, either
attract
or
repel in the direction of the line joining them. Force between
two
current elements is a bit complex, because sources are vectors
and
so,
justifiably, we can say that, in this case, the force depends
not
only
on magnitude but also on the orientation of the sources as well.
Hence
for the magnetic force, we have following Biot-Savart law
(neglect
constants),

F=(Ia) dot (Ib)/r^2 .........1.

That is not the Biot Savart law. Current is not a vector.

This seems to be a universal idiocy. Of course current is a vector.
It can have a direction...therefore it is a vector....duh.

From the fact that a current is defined as a certain dot product, it
is a scalar *by definition*
What is the direction of the current (not the current density, but the
total current, i.e. the current) in the vicinity of a metallic wire
forming an electrode in an electrolytic cell?


Practically, people are usually just interested in the magnitude,
since
the direction is confined to the direction of the wire,

You are confusing current density with curent. Suppose the wire
increased steadily in cross section along its length?

but even in
practical applications, there could be situations where one would
need to treat it as a vector. (e.g. in a plasma)

Now you are talking about a current density.
Your ignorance shines better the more you write.

You are the sort of idiot who gives engineering a bad name.

Franz

"V.K.Tamhane" wrote in message
om...
"Franz Heymann" wrote in message
...
"V.K.Tamhane" wrote in message
m...
Let us first ponder over force acting at a distance. Whenever
there
exists such a force between two bodies, the force vector always
lies
between them. The bodies, depending on their nature, either
attract
or
repel in the direction of the line joining them. Force between
two
current elements is a bit complex, because sources are vectors
and
so,
justifiably, we can say that, in this case, the force depends
not
only
on magnitude but also on the orientation of the sources as well.
Hence
for the magnetic force, we have following Biot-Savart law
(neglect
constants),

F=(Ia) dot (Ib)/r^2 .........1.

That is not the Biot Savart law. Current is not a vector.

Where Ia and Ib are two parallel current elements in the y
direction, having a distance vector r in the x direction.
This dot product should have been the final word. It is
not!

You are telling me. It is not even the initial word.

Correct equation is given by following Ampere's law. (Also known
as
Ampere's Biot-Savart law),

F= (Ia cross r) cross Ib/r^3 ........2.

That is not Ampere's law. Current is not a vector.

How is it that you can't understand simple things. If you don't
like current to be treated as a vector, then treat length of the
conductor as a vector. Do I have to simplify everything?

Current is defined as the integral over a surface of the quantity J
dot ds
where J is current density, which IS a vector
and ds is a surface element, which IS a vector.
The dot product, I hope you will realise, is a scalar quantity.

The rest was just a garbled recital of your own misconceptions, so
I
will snip it.

[snip]

What you snip is truth, but of course it is beyond your
comprehension.

Not at all. I don't confuse current with current density, like you
appear to do.

Franz

"Harold Ensle" wrote in message
k.net...
"Bilge" wrote in message
...
Harold Ensle, crackpot and idiot,

This is a sign that you know that you are wrong...
you always get more insultive in such cases.
(perhaps you should seek some counseling)


"Bilge" wrote in message

Wrong. Current is a scalar. Note that ampere's law reads:

Why do you not confess your mistake?

Because I havent made a mistake. You have.

If you did, I would just reply OK.

And if you didn't post nonsense, you wouldn't have a need to
try and defend it.

Since you can't seem to follow my simple argument above, perhaps you

Your argument is silly and naive. Which parts of the equations
I = \integral J . dS and I = dq/dt, do you not understand? Are
you trying to tell me that charge is also a vector?

will listen to authority (which seems to be your only ability):

You are an idiot. You happen to be the one with that hangup,
only after to listen to an authority, you feel compelled to
disagree. I can derive anything I post from scratch, using
my own arguments. You seem to be stuck misunderstanding passages
in books.

Griffiths states in "Introduction to Electrodynamics" page 202:

"The current at each point is actually a _vector_: ..........."

duh, not that anyone but yourself would be surprised.

Since I have a copy of griffith's and did not find that statement on
that page, I can only guess what you don't comprehend. A ``current
at each point'' is not a current, it's a current density and if
griffiths really said that, he used a very poor choice of words.

No he explained quite well, sufficient for anyone with even
meagre understanding to grasp. If you don't have the 2nd Ed.
then look on the page with section "5.3.3 Currents". It is
quite clear that he is refering to _current_ and not _current
density_.

Harold I too have that book, and the same edition as yours. He does say
what you claim on page 202 but he expressed it badly. Griffiths is a widely
used authoritative source but so is The Feynman Lectures on Physics and if
you look at volume 2 chapter 13 you will see the correct definition of
current - it is the charge that passes though a surface and is defined as I
= integral J.da where J is the current density defined as J = p.V where p is
the charge density and V is the velocity of the charge. For a current
traveling down a wire Griffith correctly defines it as I = y v where y is
the line charge density and v is the velocity in the direction of the wire -
ie a scalar. This will give the current through the a small cross section
of the wire. But he then says that it really is a vector (which it is not )
and says it really is I = y.V where V is the velocity not the velocity in
the direction of the wire. This is at the least misleading. I have a
number of books on EM and none define it as Griffiths does.

Thanks
Bill


The truely amazing thing is that you can't see it for yourself
that current is a vector.

Currents are scalars. If you don't understand the meaning of the
`.' in J . dS, look up ``scalar product''.

I know what scalar products are. And as I tried to explain
to you. This equation yields the _magnitude_ of the current
_vector(s)_ which is of course a scalar. I cannot believe that
you don't get this.

[...]
Harold, if all you are going to is make dumb comments, I'm simply
going to tell you that they're dumb. Of course it's relevant. How
can you have a field which is a field in its own right if there
exists no source of that field?

This is still irrelevant. You are arguing apples and oranges. The
fact that delxB=0 does not necessarily imply that the magnetic field
is not "a field in its own right".

curl B = J, (in magnetostatics) not zero.

Actually that was a typo. I meant del dot B.

The reason the B-field is considered
to be an artifact of a changing E-field, is because there is
no source for the B-field other than a changing E-field.

This may be the reason for the prevalent attitudes, but it is
not rigorous.

No, but you snipped the argument I made which clarified what I said.

[...]

If you could have understood what you snipped, you would
have seen your comment above was the result of your own ignorance.

....just the contrary actually.

Then why did you not understand it? Again, go look in jackson
right before the section on monopoles.

I couldn't find it. You need to be more specific. (I have the 2nd edition)

H.Ellis Ensle

"Bilge" wrote in message
...
Harry:
"Bilge" wrote in message
ue-al.net...

Scalars do not have directions. Note that the bio-savart law reads:
I dl x r, not dI x r.
SNIP

Bilge, indeed for example Alonso&Finn part 2 (Electromagnetism) treats
"I"
as only a scalar.

But W.D.Day (Intro to vector analysis for Radio and electronic eng.)
treats
"I" as a vector and writes:
F = I x B (he apparently took l=1).

When a current has one single direction as well as a magnitude it can be
presented as a vector. Maybe a little sloppy, but very handy!

I's a question of physics, not (somewhat dubious) notational
convenience.

Agreed. There is no doubt that I is a scalar and represents the charge
traveling though a surface. I have a number of EM books and it is only
Griffith that does not make it clear what it is. The two most authoritative
sources I have (if it is authority your after - I agree with Bilge it is a
matter of physics not authority) are Landau -The Classical Theory of Fields
and The Feynman Lectures - both define it correctly.

Thanks
Bill

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

"Harry" wrote in message
...

"Bilge" wrote in message
...
Harold Ensle:

"Bilge" wrote in message
e-al.net...
V.K.Tamhane:

Taking into consideration that the currents are vectors,

Currents are _NOT_ vectors. Currents are _scalars_. Current
_densities_
are vectors and a current is the surface integral of J,

I = \integral J . dS Note the scalar product.

Whoooo.....this is one of those basic physics errors that worry me.
Current is by definition a vector since it has a direction. (Is the
current going East...west...north..south....up....down...etc)

Wrong. Current is a scalar. Note that ampere's law reads:

curl B = J = \integral (curl B) . dS = \integral J . dS = I

Your equation determines the _magnitude_ of current that passes
throught
the surface. And yes, the _magnitude_ of current is a scalar.

Scalars do not have directions. Note that the bio-savart law reads:
I dl x r, not dI x r.
SNIP

Bilge, indeed for example Alonso&Finn part 2 (Electromagnetism) treats
"I"
as only a scalar.

But W.D.Day (Intro to vector analysis for Radio and electronic eng.)
treats
"I" as a vector and writes:
F = I x B (he apparently took l=1).

When a current has one single direction as well as a magnitude it can be
presented as a vector.
Maybe a little sloppy, but very handy!

NO. Current is always a vector by physical definition. It has a
direction therefore it is a vector.

No Harold. Have a look at the Feynman Lectures on Physics Chapter 13 volume
2. It is a scalar and represents the charge flowing across a surface in a
unit time. The fact some authors express it badly will not change the
physics which is I = integral J.da where J is the current density. This
means I must be a scalar. Griffith gets around his bad definition by
defining the density as I/da from his definition of I = y.V. This is
probably to get around having to define the current density before the
current - but is still bad physics.

Thanks
Bill


ANY equation that yields
a scalar value for a current is, in fact, yielding the magnitude
of the current.

This is not a grey area in physics. This is a basic fundamental
physics definition which if one is not clear about it, one needs
to review.

The fact that people are using various equations to try and
show whether it is a vector or not is completely ridiculous.
An equation does not have to give the vector. It could yield
the magnitude, or just the direction, or just a component...all
depending on the particular equation and its purpose.

H.Ellis Ensle

"Bill Hobba" wrote in message
...

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

"Harry" wrote in message
...

"Bilge" wrote in message
...
Harold Ensle:

"Bilge" wrote in message
e-al.net...
V.K.Tamhane:

Taking into consideration that the currents are vectors,

Currents are _NOT_ vectors. Currents are _scalars_. Current
_densities_
are vectors and a current is the surface integral of J,

I = \integral J . dS Note the scalar product.

Whoooo.....this is one of those basic physics errors that worry
me.
Current is by definition a vector since it has a direction. (Is
the
current going East...west...north..south....up....down...etc)

Wrong. Current is a scalar. Note that ampere's law reads:

curl B = J = \integral (curl B) . dS = \integral J . dS = I

Your equation determines the _magnitude_ of current that passes
throught
the surface. And yes, the _magnitude_ of current is a scalar.

Scalars do not have directions. Note that the bio-savart law
reads:
I dl x r, not dI x r.
SNIP

Bilge, indeed for example Alonso&Finn part 2 (Electromagnetism) treats
"I"
as only a scalar.

But W.D.Day (Intro to vector analysis for Radio and electronic eng.)
treats
"I" as a vector and writes:
F = I x B (he apparently took l=1).

When a current has one single direction as well as a magnitude it can
be
presented as a vector.
Maybe a little sloppy, but very handy!

NO. Current is always a vector by physical definition. It has a
direction therefore it is a vector.

No Harold. Have a look at the Feynman Lectures on Physics Chapter 13
volume
2. It is a scalar and represents the charge flowing across a surface in a
unit time. The fact some authors express it badly will not change the
physics which is I = integral J.da where J is the current density. This
means I must be a scalar. Griffith gets around his bad definition by
defining the density as I/da from his definition of I = y.V. This is
probably to get around having to define the current density before the
current - but is still bad physics.

Looking a little deeper into the notation what Griffith defines as current
(it is not) is technically called the vector current of a wire and is the
current multiplied by the a unit vector in the direction of the wire. That
Griffith does not make this clear is a failing on the books part.

Thanks
Bill


Thanks
Bill


ANY equation that yields
a scalar value for a current is, in fact, yielding the magnitude
of the current.

This is not a grey area in physics. This is a basic fundamental
physics definition which if one is not clear about it, one needs
to review.

The fact that people are using various equations to try and
show whether it is a vector or not is completely ridiculous.
An equation does not have to give the vector. It could yield
the magnitude, or just the direction, or just a component...all
depending on the particular equation and its purpose.

H.Ellis Ensle