# A radially pulsating charged sphere creates which of these effects?

• LCSphysicist
In summary, the electric charge of the sphere by itself will create an electric field, which will move the particle.
LCSphysicist
Homework Statement
(b) creates a static magnetic field
(c) can set a nearby electrified particle into motion.
Relevant Equations
.
I know that (a) is right, and (b) is wrong. The problem is with (c)... It seems correct to me! I can't see how this is not true. The electric charge o the sphere by itself will create an electric field, which will move the particle.

LCSphysicist said:
Homework Statement:: A radially pulsating charged sphere
(b) creates a static magnetic field
(c) can set a nearby electrified particle into motion.
Relevant Equations:: .

I know that (a) is right, and (b) is wrong. The problem is with (c)... It seems correct to me! I can't see how this is not true. The electric charge o the sphere by itself will create an electric field, which will move the particle.

Orodruin said:
"The electric charge of the sphere by itself will create an electric field, which will move the particle." is my argument.

LCSphysicist said:
"The electric charge of the sphere by itself will create an electric field, which will move the particle." is my argument.
I meant for all of the problems.

Orodruin said:
I meant for all of the problems.
(a) is correct. It emit radiation, obviously: Since the electric field configuration outside the sphere need to be oscillating, the information arriving at this point comes from the radiation that the oscillation of the sphere produces.
Now, i know there is a physical meaning for radiation, which is the term that didn't goes to zero at r infinity. If this is what the question is asking, that is, if this term is present on the potential, i can't say.

(b) This makes no sense, to create a static configuration of magnetic field, i think, we should have a constant current, or a uniform variating electric field ($\partial E / \partial t = c_{1} \neq 0$), not the case here.

(c) Should be right also. Unless, i can see in my head but not put on math, they are talking about the avarage motion of a particle. What i mean is that, the only system i can see that makes sense to say that the particle does not move, is the one in which the electric field attract the particle, the magnetic field generated by it curves it path so that it returns at the same position after a period, and so tecnically it didn't move. That i can't prove.

LCSphysicist said:
(a) is correct. It emit radiation, obviously: Since the electric field configuration outside the sphere need to be oscillating, the information arriving at this point comes from the radiation that the oscillation of the sphere produces.
Now, i know there is a physical meaning for radiation, which is the term that didn't goes to zero at r infinity. If this is what the question is asking, that is, if this term is present on the potential, i can't say.
Here is a hint: there is no electromagnetic monopole radiation.

berkeman
Orodruin said:
Here is a hint: there is no electromagnetic monopole radiation.
I can think about it late, but thank you. By now, i would like to understand how can "c" be wrong.

Why do you think it wrong ?

hutchphd said:
Why do you think it wrong ?
OOp, right in time XD.
Because the answer provided is only a.

Where is this from?

LCSphysicist said:
OOp, right in time XD.
Because the answer provided is only a.
Orodruin said:
Here is a hint: there is no electromagnetic monopole radiation.
I don't know it it will help you @LCSphysicist , but think about how an antenna works. You drive a voltage differentially between the two antenna elements to create a differential voltage and current, and that's what creates the EM field that propagates away from the antenna. If you drive the two antenna elements with the same common-mode current, there is no differential current, so no launching of the EM waveform.

LCSphysicist said:
Since the electric field configuration outside the sphere need to be oscillating
What is the field outside a uniformly charged spherical shell of radius r?

LCSphysicist said:
OOp, right in time XD.
Because the answer provided is only a.
Well, that is wrong, so …

## 1. How does a radially pulsating charged sphere create electromagnetic radiation?

A radially pulsating charged sphere creates electromagnetic radiation by accelerating the charged particles within it. As the particles move back and forth, they create changing electric and magnetic fields, which then propagate outward as electromagnetic waves.

## 2. What is the relationship between the frequency of pulsation and the frequency of the emitted radiation?

The frequency of the emitted radiation is equal to the frequency of pulsation of the charged sphere. This is because the frequency of the emitted radiation is directly determined by the frequency of the oscillating charged particles.

## 3. Can a radially pulsating charged sphere emit different types of electromagnetic radiation?

Yes, a radially pulsating charged sphere can emit a range of electromagnetic radiation, including radio waves, microwaves, infrared, visible light, ultraviolet, X-rays, and gamma rays. The specific type of radiation emitted depends on the frequency of pulsation and the energy of the charged particles.

## 4. How does the amplitude of pulsation affect the intensity of the emitted radiation?

The amplitude of pulsation directly affects the intensity of the emitted radiation. A larger amplitude of pulsation results in a higher intensity of radiation, while a smaller amplitude results in a lower intensity. This is because a larger amplitude means the charged particles are moving with a greater distance and speed, creating stronger electric and magnetic fields and thus more intense radiation.

## 5. Can a radially pulsating charged sphere emit radiation even when it is not pulsating?

No, a radially pulsating charged sphere can only emit radiation while it is pulsating. When the pulsation stops, the acceleration of the charged particles also stops, and thus no electromagnetic radiation is produced. However, the emitted radiation may continue to propagate outward for some time after the pulsation has ceased.

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