Why accelerated charge emits electromagnetic radiation

[GAGAN SHARMA]

Its well known that an accelerated charge emits electromagnetic radiation. Then why the orbiting electrons in atom merge in nucleus after some time.

 

[maniaciswicke]

Uhhhh they dont?
They will continue to orbit or they will be ejected completely
Electrons don't fall into the nucleus of an atom

 

[Bob S]

Electrons in the lowest bound states of atomic orbits cannot radiate, because of energy conservation. The electrons cannot transition to lower energy states. But in certain atoms, like beryllium-7 (lifetime 53.25 days), the proton can "absorb" an electron in the 1s state and decay to a bound neutron (in lithium-7).
Bob S

 

[jtbell]

orbiting electrons in atom

Atomic electrons don't "orbit" in the classical sense.

 

[mikelepore]

This was the question that made people realize that Rutherford's idea of the atom as a little solar system was an imperfect model - that the electrons couldn't radiate waves without long energy and having their orbits decay and spiral into the nucleus. Bohr suggested to Rutherford fixing the model by saying that electrons don't radiate waves as long as they stay in certain stable orbits. Bohr's idea established the "n" quantum number.

 

[Andrew Mason]

Its well known that an accelerated charge emits electromagnetic radiation. Then why the orbiting electrons in atom (do not) merge in nucleus after some time.

Welcome to PF.

It may be that your premise is incorrect. Whether a uniformly accelerated charge emits radiation is still a matter of debate. See:

http://www.gi.alaska.edu/~chungsangng/uac.pdf

and

https://www.physicsforums.com/showthread.php?t=65767

AM

 

[Bob S]

It may be that your premise is incorrect. Whether a uniformly accelerated charge emits radiation is still a matter of debate.

Panofsky and Phillips "Classical Electricity and Magnetism" First edition, page 301 eqn(19-19) shows that a uniformly accelerating charge radiates. It is proportional to (dv/dt)².
Bob S

 

[Bob_for_short]

It may be that your premise is incorrect. Whether a uniformly accelerated charge emits radiation is still a matter of debate.

According to the Maxwell, electromagnetic field equations it radiates for sure.

Another thing is how to take this fact into account in the electron, mechanical equations. There have been many attempts, all unsuccessful except mine.

 

[jtbell]

Whether a uniformly accelerated charge emits radiation is still a matter of debate.

The acceleration in a circular orbit (which is what people were thinking in terms of, in Bohr's day) is not uniform acceleration.

 

[Bob_for_short]

Its well known that an accelerated charge emits electromagnetic radiation. Then why the orbiting electrons in atom does not merge in nucleus after some time.

It nearly merges - the neutral atom is so small that is invisible with an eye. It is invisible even in a microscope.

 

[Andrew Mason]

Panofsky and Phillips "Classical Electricity and Magnetism" First edition, page 301 eqn(19-19) shows that a uniformly accelerating charge radiates. It is proportional to (dv/dt)².
Bob S

Well, a charge that accelerates uniformly due to its interaction with an electro-magnetic field will radiate. But is that caused by the interactions of the charge with the field or is it caused by the acceleration?

If it was the acceleration, then acceleration due to gravity should also produce radiation. And, since gravitational acceleration is locally equivalent to moving at uniform speed in a gravitational field, a stationary charge in a gravitational field should radiate. But neither does.

AM