Question

Why does not electron release any energy (according to Maxwell's law :all the accelerating charged particle will release energy in form of electromagnetic waves) while orbiting around the nucleus for only the fixed values of angular momentum L=nh/2pi ?

Answer 1

Because that law is only applicable for macroscopic particles while electron is microscopic :)

Answer 2

@.Sam. @ghazi @sauravshakya @UnkleRhaukus

Answer 3

first of all electron releases energy when it falls from a higher state to a lower state...that is from high energy level to low energy orbital

Answer 4

bohr said that when an electrn revolves in certain orbits it doesnt radiate energy what is the REAL reason?

Answer 5

The best answer: This was just an assumption in order to explain scientific results when it came to the hydrogen atom. In reality, the electron would exhibit a duality between a matter and wave form and thus can't be explained classically via Maxwell's law. Thus explains the existence of quantum physics.

Answer 6

According to Neil’s Bohr’s, an electron will revolve in those shell, in which its energy will be quantanized. Such shells are called stationary energy level. Electron will release energy only which it changes from higher level to lower level.

Answer 7

@dominusscholae then how can we explain this using quantum mechanics

Answer 8

Bohr's Atomic..Model..Gives ans for this

Answer 9

@mathavraj There are different interpretations regarding why this is the case. The existence of a "couloumb force" is theorized to prevent the electron from collapsing into the nucleus through repulsion. Yet, the quantum viewpoint when it comes to atoms is more relevant. We explain this in a quantum viewpoint in terms of the probability a particle is going to be in a certain location in space. We can't explain in classical terms since microscopically they fail. What we can say though, is that the electron will MOST probably be in distinct regions in space around the atom due to its wavelike nature, with a VERY miniscule probability that the electron is INSIDE the atom. Under this view, though, the regions described are not orbits, but rather Orbitals. There are different types, but basically the electron can occupy in a region such that, when plotted, resembles a sphere, a dumbbell shape, and other more complicated volumes.

Answer 10

thanks but i think there is more to this that cant be explained easily!

Answer 11

np :). Don't worry, this is a pretty hard concept for many to understand/investigate.

Answer 12

@mathavraj the simple answer is my 1st reply -.-

Answer 13

@mathavraj @dominusscholae @yahoo! see, maxwell rule is for ACCELERATED charged particle revolving around ....so does it look like that revolving electron around nucleus is accelerated ...i guess no..because electron revolves around nucleus with a constant angular velocity (that is approximately velocity of light) so acceleration or angular acceleration is zero \[\tau= I*\alpha= \frac{ dL }{ dt }\] now alpha will be zero ...AS YOU SAID CONSTANT ANGULAR MOMENTUM...therefore no accelerated motion no emission of electromagnetic wave...hope that makes sense..... :)

Answer 14

@mathavraj your question says fixed angular momentum therefore angular acceleration is zero... in the above comment L is angular momentum

Answer 15

@ghazi the thing is under the regular orbit model, the electron still would be accelerating since it has acceleration towards the center via centripetal acceleration. Like DLS and I said, a classical law such as Maxwell's doesn't apply to microscopic systems such as these. To explain where the concept of a constant angular momentum comes from, bohr, in forming a theory, assumed that the electron acted like a standing wave around the atom, having certain wavelength being inspired by de Broglie wavelength. Assuming a circular orbit of radius r, the wavelength would be 2pi*R/n, n being the principal quantum number. Setting this equal to de Broglie wavelength yields mv = nh/2pi*r. Since angular momentum = mvr in a circular orbit yields mvr = L = nh/2pi.

Answer 16

Thing is the above reasoning would only explain results for hydrogenlike atoms. The previous post by me on orbitals more reflects the nature of atoms that are not hydrogenlike.

Answer 17

what if i consider it hydrogen...orbital

Answer 18

There still are orbitals with hydrogen, and with orbitals, there are certain levels of energy involved. Still electrons in hydrogen resemble this model more than Bohr, and the electrons in hydrogen don't necessarily move in a certain orbit, rather a certain region. The thing I'm saying is that is that Bohr's theory about discrete levels of energy and angular momentum hold for atoms like hydrogen.

Answer 19

okay...got your point