Does a free falling charged ball emit radiation?

[John Ye]

Without considering Earth magnetic field(the charged ball is only attracted by gravity), It does not emit radiation.

The key point is: any charge accelerated by only one force will not emit energy.

IT emits energy only when it's being decelerated.

Or when it's being exerted by more than one force. A typical case is that the charge is running in circular track.

The charge gains energy while being accelerated, releases energy while being decelerated.

Without considering Earth magnetic field(the charged ball is only attracted by gravity), It does not emit radiation.

The key point is: any charge accelerated by only one force will not emit energy.

IT emits energy only when it's being decelerated.

Or when it's being exerted by more than one force. A typical case is that the charge is running in circular track when it's being affected by both electric force and magnetic force. Electrons in cyclotron radiate energy.

In general, the charge gains energy while being accelerated, releases energy while being decelerated.

When an electron is circulating proton, it's only exerted one force---the Coulomb force, it does not emit energy.

 

Based on one force rule,  an electron is not emitting energy  while circulating proton. It's only exerted one force---the Coulomb force.

Edited September 5, 2018 by John Ye
REPEATED WORDS

[studiot]

Your proposal has two planks that appear to me to be entirely separate.

Repeated after extended rebuttal by swansont.

 

1) Charge only radiates when it is decelerated

2) Charge may radiate when it is accelerated by more than one force.

 

How is this proposal compatible with the Larmor formula?

https://en.wikipedia.org/wiki/Larmor_formula

 

A cathode ray is accelerated by only one force in a simple cathode ray tube and is yet known to emit (dangerous) Xrays.
This is direct observational evidence against your proposal.

 

Of course if more than one force act on a point particle they combine vectorially to produce a single resultant.
So how Why does your proposal not also contravene the laws of mechanics?

 

[swansont]

8 hours ago, John Ye said:

 The key point is: any charge accelerated by only one force will not emit energy.

An electron moving at constant speed (i.e. no force on it) enters a magnetic field. It will experience a magnetic force and beging to move in a spiral, and emit cyclotron radiation.

8 hours ago, John Ye said:

IT emits energy only when it's being decelerated.

Or when it's being exerted by more than one force. A typical case is that the charge is running in circular track when it's being affected by both electric force and magnetic force. Electrons in cyclotron radiate energy.

They only have the tangential force to keep them moving at the required speed, because they radiate and lose energy. If you only had the magnetic field, and they did not radiate, there would be no reason to have an electric field to add energy to them.

8 hours ago, John Ye said:

In general, the charge gains energy while being accelerated, releases energy while being decelerated.

Explain how radio waves from an antenna are continuous. Explain further how the spectrum does not have all of the higher-frequency harmonics you would expect if you did not have a sine wave source.

Evidence would be preferred.

8 hours ago, John Ye said:

When an electron is circulating proton, it's only exerted one force---the Coulomb force, it does not emit energy.

Electrons in atoms radiate all the time. It's just that it's in discrete values and it does not happen in the ground state.

8 hours ago, John Ye said:

Based on one force rule,  an electron is not emitting energy  while circulating proton. It's only exerted one force---the Coulomb force.

You have not provided any evidence that such a rule exists anywhere outside of your mind.  

[studiot]

Just to emphasise the point

https://en.wikipedia.org/wiki/Crookes_tube

 

Note that there are no magnetic or gravitational forces involved, only electrostatic ones.

Note that the comment in the article that

Wilhelm Röntgen discovered X-rays using the Crookes tube in 1895

[John Ye]

38 minutes ago, swansont said:

An electron moving at constant speed (i.e. no force on it) enters a magnetic field. It will experience a magnetic force and beging to move in a spiral, and emit cyclotron radiation.

This case can be considered as a deceleration. Their speed(direction part) is changed by magnetic field, and emit energy, their tangent speed will become less and less, they can't run forever.

46 minutes ago, swansont said:

Explain how radio waves from an antenna are continuous. Explain further how the spectrum does not have all of the higher-frequency harmonics you would expect if you did not have a sine wave source.

Evidence would be preferred.

When a half sine oscillation stimulates water, water wave is continuous. Because the stop time is too short, indide one wave period. 

Similarly, we keeps throwing stones into water, we can adjust the repeating time interval, get a continuous water wave.

3 hours ago, studiot said:

A cathode ray is accelerated by only one force in a simple cathode ray tube and is yet known to emit (dangerous) Xrays.
This is direct observational evidence against your proposal.

Yes. They emit X ray because they hit metal anode, and be suddenly stopped. Their kinetic energy is released in the form of X ray

Before hitting anode, they gain energy from electric field. In accelerating state, no X ray is released.

[studiot]

17 minutes ago, John Ye said:

Before hitting anode, they gain energy from electric field. In accelerating state, no X ray is released.

What evidence do have for this assumption on your part?

How would you test the truth or falsity of it?

Edited September 5, 2018 by studiot

[John Ye]

1 minute ago, studiot said:

What evidence do have for this assumption on your part?

It can be analyzed by the experiments done before. So it is actually not an assumption.  If someone wants to make new experiment to prove it, the test must be redesigned for that purpose.

Past experiments have already shown that the X ray is coming from anode, not in the accelerating midway

 

[studiot]

5 minutes ago, John Ye said:

Past experiments have already shown that the X ray is coming from anode, not in the accelerating midway

Your claim right there that the only EM radiation occurs at the anode and nowhere else is the problem.

I don't disagree that radiation is generated at the anode, and never have done.
Of course it will, the anode accelerates the electrons, as does striking the glass tube or any phosphor.

Note the difference between at the anode and your 'from the anode'.
X rays from the anode are not from the cathode rays!
 

Why do the electrons striking the glass, not emit Xrays?
These come from the glass/phosphor itself.

But it is generated elsewhere as well.

Read the Wiki article properly

[John Ye]

38 minutes ago, studiot said:

Your claim right there that the only EM radiation occurs at the anode and nowhere else is the problem.

I don't disagree that radiation is generated at the anode, and never have done.
Of course it will, the anode accelerates the electrons, as does striking the glass tube or any phosphor.

Note the difference between at the anode and your 'from the anode'.
X rays from the anode are not from the cathode rays!
 

Why do the electrons striking the glass, not emit Xrays?
These come from the glass/phosphor itself.

But it is generated elsewhere as well.

Read the Wiki article properly

X ray from anode falls into two categories. On is emitted by the suddenly broke high speed electrons (continuous spectrum), the other is emitted by anode material's atom electrons' transition, which has discrete spectrum.

Both metal anode and glass covered anode generate X ray. But glass hitting is less effective, because glass is more sparse than metal.  It's not effective to beak electrons, generate less x ray. 

Because glass is less effective to break the electron, it generates less X ray (than metal, heavy metal) , more violet and ultraviolet rays. If electron runs fast enough, we can detect X.

[studiot]

20 minutes ago, John Ye said:

X ray from anode falls into two categories. On is emitted by the suddenly broke high speed electrons (continuous spectrum), the other is emitted by anode material's atom electrons' transition, which has discrete spectrum.

Both metal anode and glass covered anode generate X ray. But glass hitting is less effective, because glass is more sparse than metal.  It's not effective to beak electrons, generate less x ray. 

Because glass is less effective to break the electron, it generates less X ray (than metal, heavy metal) , more violet and ultraviolet rays. If electron runs fast enough, we can detect X.

 

You didn't read the article then.

Or my question properly.

Fair enough it's a free world.

But there's no point talking further to you.

[John Ye]

5 hours ago, studiot said:

A cathode ray is accelerated by only one force in a simple cathode ray tube and is yet known to emit (dangerous) Xrays.
This is direct observational evidence against your proposal.

Electrons hits glass, and hits gas atoms.

The tube is not 100% vacuum.

The electrons hitting something are exerted two forces, not one. 

[Ghideon]

21 minutes ago, John Ye said:

The electrons hitting something are exerted two forces, not one. 

Please explain how the two forces does not combine vectorially, I fail to get that from the discussion so far. See studiots comment:

5 hours ago, studiot said:

Of course if more than one force act on a point particle they combine vectorially to produce a single resultant.

 

[John Ye]

10 minutes ago, Ghideon said:

Please explain how the two forces does not combine vectorially, I fail to get that from the discussion so far. See studiots comment:

Velocity is combined when electron hitting tube glass.

Let's think a running car hits a big tree.

If car  crashes to the tree while  driver is still stepping on accelerator pedal, the car has two forces on it. One is engine force, the other is tree's reaction force.

The result is a bad car and hurting driver.

Combined velocity is very very big, of course a minus value.

 

While car hits wall, cara's kinetic energy is converted to other forms and  suddenly released, thermal, probably light, sound, electromagnetic radiation, etc.

[swansont]

2 hours ago, John Ye said:

This case can be considered as a deceleration.

No, the magnetic force is perpendicular to the motion. It does no work on the particle. 

2 hours ago, John Ye said:

Their speed(direction part) is changed by magnetic field, and emit energy, their tangent speed will become less and less, they can't run forever.

If they did not radiate, they would emit no energy. The fact that they do, and that you admit that they do, is in complete contradiction to your position.

2 hours ago, John Ye said:

When a half sine oscillation stimulates water, water wave is continuous. Because the stop time is too short, indide one wave period. 

Prove it. Give me evidence.

2 hours ago, John Ye said:

Similarly, we keeps throwing stones into water, we can adjust the repeating time interval, get a continuous water wave.

Show this happening. Resulting in a pure sine wave of constant amplitude.

 

2 hours ago, John Ye said:

Past experiments have already shown that the X ray is coming from anode, not in the accelerating midway

Because the amount of power you radiate depends on the acceleration, which is much larger in the target.

14 minutes ago, John Ye said:

Velocity is combined when electron hitting tube glass.

Let's think a running car hits a big tree.

If car  crashes to the tree while  driver is still stepping on accelerator pedal, the car has two forces on it. One is engine force, the other is tree's reaction force.

The result is a bad car and hurting driver.

Combined velocity is very very big, of course a minus value.

 

An electron in a CRT is not being accelerated while it collides. That part happens earlier in the process.

[John Ye]

19 minutes ago, swansont said:

No, the magnetic force is perpendicular to the motion. It does no work on the particle. 

If they did not radiate, they would emit no energy. The fact that they do, and that you admit that they do, is in complete contradiction to your position.

Prove it. Give me evidence.

Show this happening. Resulting in a pure sine wave of constant amplitude.

 

Because the amount of power you radiate depends on the acceleration, which is much larger in the target.

An electron in a CRT is not being accelerated while it collides. That part happens earlier in the process.

In CRT, electron is attracted by anode screen, at the same time, is deflected by deflection magnetic field or deflection electric field. So it will emit radiation before hitting screen, and on hitting screen.

Or we can put it this way: for an electron running in a straight line, accelerating one will not emit energy, decelerating one will. 

So the free falling change will not emit radiation.

[studiot]

1 hour ago, John Ye said:

Velocity is combined when electron hitting tube glass.

Neither velocity (nor momentum) is a Force.

You specifically said more than one force, which excludes all other vecotors.

So yes, thank you Ghideon, I still await a proper explanation of this claim.

+1 for reminding me.

[John Cuthber]

16 hours ago, John Ye said:

IT emits energy only when it's being decelerated.

 

Imagine two electrons travelling down an X ray tube, They both reach the anode. One hits something- another electron for example, and comes to a halt (emitting Xrays).

 

Now look at it from the point of view of the other electron. 

It is watching its friend as they both pass down the tube.

Suddenly another electron rushes up and crashes into  it and causes it to accelerate and emit Xrays.

 

It's the same event and the same Xray emission

But from one point of view, it's acceleration- and from the other perspective it is deceleration.

So, how can there be a distinction between the two since it's just a matter of perspective?

 

 

[swansont]

5 hours ago, John Ye said:

In CRT, electron is attracted by anode screen, at the same time, is deflected by deflection magnetic field or deflection electric field. So it will emit radiation before hitting screen, and on hitting screen.

So you agree, the acceleration occurs before the collision, and your previous claim was in error.

Quote

Or we can put it this way: for an electron running in a straight line, accelerating one will not emit energy, decelerating one will. 

Repeating this does not make it true. You need to provide e v i d e n c e.

Moving is a circle is an acceleration, and not a deceleration — though physicists rarely use this term, since acceleration is a vector; it's simply a matter of your choice of coordinates and frame of reference. One frame's acceleration is another frame's deceleration, and this is a trivial way to know that you are wrong, as John describes above. 

 

[John Ye]

6 hours ago, studiot said:

Neither velocity (nor momentum) is a Force.

You specifically said more than one force, which excludes all other vecotors.

So yes, thank you Ghideon, I still await a proper explanation of this claim.

+1 for reminding me.

Running ( been accelerated or not) electrons hitting something, their acceleration value is changed, their velocity value is changed. They emit energy. If no this interaction, they will continue to run in a constant speed, without energy emitted.

 

[John Ye]

4 hours ago, swansont said:

So you agree, the acceleration occurs before the collision, and your previous claim was in error.

Repeating this does not make it true. You need to provide e v i d e n c e.

Moving is a circle is an acceleration, and not a deceleration — though physicists rarely use this term, since acceleration is a vector; it's simply a matter of your choice of coordinates and frame of reference. One frame's acceleration is another frame's deceleration, and this is a trivial way to know that you are wrong, as John describes above. 

 

moving electron entering  magnetic field leads to a circle movement. As I said previously, it will slow down, and finally it will stop.

Many experiments can serve as evidence.  Electrons in cyclotron will finally stop after switching off the electric field while keeping magnetic deflection.

5 hours ago, John Cuthber said:

 

Imagine two electrons travelling down an X ray tube, They both reach the anode. One hits something- another electron for example, and comes to a halt (emitting Xrays).

 

Now look at it from the point of view of the other electron. 

It is watching its friend as they both pass down the tube.

Suddenly another electron rushes up and crashes into  it and causes it to accelerate and emit Xrays.

 

It's the same event and the same Xray emission

But from one point of view, it's acceleration- and from the other perspective it is deceleration.

So, how can there be a distinction between the two since it's just a matter of perspective?

 

 

Both electrons' speed is relative to the anode, each relative to other one does not make any sense.

For X ray can be generated only by this speed.

It is the interaction between electrons and anode that makes them to reduce speed and release energy.

Edited September 6, 2018 by John Ye

[John Cuthber]

5 hours ago, John Ye said:

Both electrons' speed is relative to the anode, each relative to other one does not make any sense.

For X ray can be generated only by this speed.

It is the interaction between electrons and anode that makes them to reduce speed and release energy.

Did you miss the point, or are you ignoring it?

Do you really not understand the idea of relative velocity?

[John Ye]

1 hour ago, John Cuthber said:

Did you miss the point, or are you ignoring it?

Do you really not understand the idea of relative velocity?

John, I did not miss your point.

For generating X ray, electrons must be running fast enough toward anode and hit anode. Do you agree this?

So the meaningful speed is electron's velocity relative to anode.

Each one's speed relative to other is not meaningful.

The electrons will not emit energy before hitting anode.

the electrons constitutes so called cathode  ray, and they are not having exactly  the same velocity. some of them may slower than others.

from one electron's point of view, other electrons is not stationary,  acceleration and velocity varies.

but these values make no sense. 

the meaningful value is the speed relative to anode.

[swansont]

9 hours ago, John Ye said:

moving electron entering  magnetic field leads to a circle movement. As I said previously, it will slow down, and finally it will stop.

Because it radiates. Because it is accelerating.

There is no external force on it causing it to slow down. If it did not radiate, it would not slow.

9 hours ago, John Ye said:

Many experiments can serve as evidence.  Electrons in cyclotron will finally stop after switching off the electric field while keeping magnetic deflection.

Because they radiate. Because they are accelerating.

There is no external force on them causing them to slow down. If they did not radiate, they would not slow.

 

None of this supports your claim.

1 hour ago, John Ye said:

John, I did not miss your point.

For generating X ray, electrons must be running fast enough toward anode and hit anode. Do you agree this?

Or, the anode must be moving fast enough when it hits a stationary electron. Speed is relative.

1 hour ago, John Ye said:

So the meaningful speed is electron's velocity relative to anode.

Each one's speed relative to other is not meaningful.

The electrons will not emit energy before hitting anode.

the electrons constitutes so called cathode  ray, and they are not having exactly  the same velocity. some of them may slower than others.

from one electron's point of view, other electrons is not stationary,  acceleration and velocity varies.

In John's example they are. It's a thought experiment.

1 hour ago, John Ye said:

but these values make no sense. 

the meaningful value is the speed relative to anode.

Yes. But one can choose a frame where the electron is at rest, and is accelerated by the collision, and the result is the same — you get radiation. The notion that acceleration and deceleration have some fundamental difference is naive from a physics standpoint.

[John Ye]

31 minutes ago, swansont said:

Because it radiates. Because it is accelerating.

There is no external force on it causing it to slow down. If it did not radiate, it would not slow.

In fact, it will slow down. Do you agree this? 

We can say that it slows down because it emits energy. Or we can say that it radiates because it has a minus acceleration value. 

The physical nature is that the interaction between electron and magnetic field makes it radiates energy

39 minutes ago, swansont said:

Because they radiate. Because they are accelerating.

Any radiating charge in magnetic field only (without other field) will be slowing down and finally completely stop. Its acceleration value must be below zero.

 

47 minutes ago, swansont said:

Because it radiates. Because it is accelerating.

There is no external force on it causing it to slow down. If it did not radiate, it would not slow.

Because they radiate. Because they are accelerating.

There is no external force on them causing them to slow down. If they did not radiate, they would not slow.

 

None of this supports your claim.

Or, the anode must be moving fast enough when it hits a stationary electron. Speed is relative.

In John's example they are. It's a thought experiment.

Yes. But one can choose a frame where the electron is at rest, and is accelerated by the collision, and the result is the same — you get radiation. The notion that acceleration and deceleration have some fundamental difference is naive from a physics standpoint.

Swansont, let's begin from the simplest case. It is easy to figure out. When a electron was attracted by only one non deflection force, it is moving in straight line with a plus acceleration value, it goes faster and faster. I said, it Will NOT emit energy. Do not agree this?

[swansont]

1 hour ago, John Ye said:

In fact, it will slow down. Do you agree this? 

Yes.

Quote

We can say that it slows down because it emits energy. Or we can say that it radiates because it has a minus acceleration value. 

What is the force causing the acceleration that makes it slow down?

Quote

The physical nature is that the interaction between electron and magnetic field makes it radiates energy

Specifically, the acceleration.  

Quote

Any radiating charge in magnetic field only (without other field) will be slowing down and finally completely stop. Its acceleration value must be below zero.

Your assertion is that the negative acceleration causes the radiation, correct? What is the external interaction that is giving you this acceleration?

Quote

Swansont, let's begin from the simplest case. It is easy to figure out. When a electron was attracted by only one non deflection force, it is moving in straight line with a plus acceleration value, it goes faster and faster. I said, it Will NOT emit energy. Do not agree this?

We agree that you have said this. Again and again; assertion without justification. But you are wrong — it will radiate. I gave a link to the physics some time ago.