Will an Accelerated Charge in an Isolated Universe Emit EM Waves?

  • Thread starter siddharth
  • Start date
In summary, the conversation discusses the concept of accelerating a charge and the resulting production of electromagnetic waves. The question of whether this would still occur in a universe with only one electron is raised, and it is determined that the energy conservation principle would not be violated. The conversation also explores the idea of using a spring to accelerate the charge, and how it would affect the situation. Ultimately, it is concluded that the oscillating charge would indeed produce EM waves, but this would not violate energy conservation as the energy from the spring's oscillations would be used up. The concept of a non-inertial frame of reference is also discussed.
  • #1
siddharth
Homework Helper
Gold Member
1,143
0
I learned that when we accelerate a charge we get EM radiation. If I have a universe with only 1 electron in it so that no other Electric Field exists, and I then procced to accelerate the charge, will I still get EM waves?

(Neglecting mass of charge)

Since there is no other force on this charge, because the Electric field cannot act on iteself, I need no external force to accelerate it. Therefore i can keep producing energy in form of em waves.

If yes, then is the energy conservation not violated?
 
Physics news on Phys.org
  • #2
How do you propose accelerating the charge?
Garth
 
  • #3
If the charge were massless it would move at the speed of light (special relativity) so then you couldn't accelerate it. Therefore it has mass. If you accelerate its mass it gets increasing kinetic energy, but it also radiates, losing energy. Energy is conserved, and the radiated energy is subtracted from the kinetic energy, slowing the acceleration down.
 
  • #4
selfAdjoint said:
If the charge were massless it would move at the speed of light (special relativity) so then you couldn't accelerate it. Therefore it has mass. If you accelerate its mass it gets increasing kinetic energy, but it also radiates, losing energy. Energy is conserved, and the radiated energy is subtracted from the kinetic energy, slowing the acceleration down.
In what frame of reference is the lone electron accelerating or decelerating?

Garth
 
  • #5
Lets say I use a spring to accelerate the charge in SHM. Now i have only the spring and the charge in the universe. Now what would happen. Would the E-fields due to spring affect the situation in anyway?
 
  • #6
selfAdjoint said:
If the charge were massless it would move at the speed of light (special relativity) so then you couldn't accelerate it. Therefore it has mass. If you accelerate its mass it gets increasing kinetic energy, but it also radiates, losing energy. Energy is conserved, and the radiated energy is subtracted from the kinetic energy, slowing the acceleration down.


Also, Because of the fact that the charge is alone in the universe and there is no other field (In my first post). There is no external force which can act on the charge. Therefore how can it lose energy and slow down without an external force?

Modifying my last post let us assume that the spring is made of a particle which does not have charge but exhibits, say strong interactions.
 
  • #7
You can't have it both ways! You can't say "accelerate a charge" and then say "there is no which can act on the charge". If there is no external force, then you can't accelerate it.

You said before "Lets say I use a spring to accelerate the charge in SHM." Okay, the spring is exerting an external force. In order to do that, the spring has to be attached to something or at least stationary in some frame of reference.
 
  • #8
siddharth said:
Modifying my last post let us assume that the spring is made of a particle which does not have charge but exhibits, say strong interactions.
Then its not alone in the universe! My questions are centred on Mach's principle and the thought that if a particle were alone in the universe then it could not move or accelerate because there would be no way of measuring what it is moving with respect to.

If you had two particles, they could be two electrons, then they would repel each other and would accelerate away from each other. You could tie a non-inertial frame of reference to either particle, or an inertial frame of reference to an imaginary spot in the middle at the centre of mass.

Garth
 
  • #9
I am sorry for not making my question clearer. I hope this clarifies it.

My spring system is made of two particles which exhibit the same type properties except for charge. The particle on the left end of the spring system does not possesses the property of charge. The spring itself is made of particles which does not posses the property of charge. The particle on the right end of the system has charge.

Now, when the spring undergoes SHM the center of mass of the system is at rest. Therefore I have a non-inertial frame. Furthermore I can accelerate the charge by forces other than coulumbic forces.

Therefore i ensure that the only electric field is due to the charge. Now my question is will the oscillating charge produce EM waves. If yes, then does it not violate the conservation of energy?
 
  • #10
siddharth said:
Therefore I have a non-inertial frame.

Read as: Therefore I have an inertial frame
 
  • #11
siddharth said:
I am sorry for not making my question clearer. I hope this clarifies it.

My spring system is made of two particles which exhibit the same type properties except for charge. The particle on the left end of the spring system does not possesses the property of charge. The spring itself is made of particles which does not posses the property of charge. The particle on the right end of the system has charge.

Now, when the spring undergoes SHM the center of mass of the system is at rest. Therefore I have a non-inertial frame. Furthermore I can accelerate the charge by forces other than coulumbic forces.

Therefore i ensure that the only electric field is due to the charge. Now my question is will the oscillating charge produce EM waves. If yes, then does it not violate the conservation of energy?
Yes and No. Yes the charge will emit EM radiation, and No energy conservation is not violated as the energy of the spring's oscillations will be used up.
Both two particles will also radiate gravitational waves, (very weakly) and the system will loose 'kinetic' mass as these two forms of radiation leak energy into empty space.

Garth
 

FAQ: Will an Accelerated Charge in an Isolated Universe Emit EM Waves?

What is a seemingly naive question?

A seemingly naive question is a question that appears to be simple or obvious, but actually requires a more complex or nuanced answer.

Why are seemingly naive questions important in science?

Seemingly naive questions can often lead to new discoveries or insights in science. They can challenge existing beliefs and lead to further exploration and understanding of a topic.

How can scientists differentiate between a seemingly naive question and a truly naive question?

Scientists can differentiate between the two by considering the context in which the question is asked and evaluating the thought process behind it. A seemingly naive question often comes from a place of curiosity and a desire to understand, while a truly naive question may come from a lack of knowledge or understanding.

Are there any benefits to asking seemingly naive questions?

Yes, there are several benefits to asking seemingly naive questions. They can stimulate critical thinking, encourage open-mindedness, and lead to new perspectives and ideas.

How can scientists encourage the asking of seemingly naive questions in their research?

Scientists can encourage the asking of seemingly naive questions by creating a safe and open environment for discussion and inquiry. They can also actively listen to and value all questions, regardless of how simple or complex they may seem.

Similar threads

B Why doesn't a charged particle moving at a constant speed radiate?
Replies
2
Views
561
I Energy emitted by EM sources under constructive interference
Replies
7
Views
1K
B Is a Spark Necessary for the Production of EM Waves in the Hertz Experiment?
Replies
18
Views
2K
I EM field and EM wave
Replies
3
Views
824
I How does the magnetic component of an EM wave affect surroundings?
Replies
8
Views
1K
B Understanding the electric field
Replies
16
Views
766
Does constant DC current in curved wire produce EM wave?
2
Replies
38
Views
2K
B Can charges move without a field? How charges redistribute without it?
Replies
16
Views
916
I Destat Apparatus - Exploring The Physics Behind It
Replies
9
Views
1K
A Electric and magnetic field lines in a plane wave of finite extent
Replies
1
Views
540

Hot Threads

Recent Insights

Back
Top