# Hydrogen atom obeying classical mechanics rather than quantum mechanics

1. Jul 22, 2009

### jessiepink

Suppose that the electron in the hydrogen atom obeyed classical mechanics rather than quantum mechanics. Why should such a hypothetical atom emit a continuous spectrum rather than the observed line spectrum?

So far I have: quantum mechanics deals with the smallest possible piece of a system. The behaviors of such pieces will be different than the behaviors of a system at whole. The atom will not emit a line spectrum b/c it will not be moving like a light wave/particle.

2. Jul 22, 2009

### turin

I think that you need to understand classical electromagnetism to answer this question, and it should probably be in the advanced physics forum. What course is this for? And at what level?

3. Jul 24, 2009

### jessiepink

The class is Intro to Physics 2.

4. Jul 27, 2009

### turin

I don't know why you are expected to be able to address this question, then.

The only hints that I can think of are:
What is the electromagnetic consequence of accelerating charge?
What kind of motion does the electron in a classical hydrogen atom execute?
What happens to the motion of an orbiting object when it loses energy?

These hints are given in no particular order, and, in fact, they are iterative.

5. Mar 22, 2011

### Nitnaes

This question looks to be from Modern Physics (3rd edition) by Serway, Moses and Moyer, chapter 4 Q2 (as it is the same word for word). So I will answer to an according level of physics.

In classical mechanics the e- is not restricted to being in atomic levels, ie. it can be at any distance in orbit in relation to the nucleus. If the e- moves closer to the nucleus it will do so gradually and therefore emit energy continuously at varying degrees. This will cause the continuous spectrum talked about in the question.

In quantum mechanics the e- is restricted to being certain distances from the nucleus known as atomic levels (or shells). When an e- moves down quantum levels towards the nucleus it will emit energy instantaneously. This means that the energy is emitted in one "packet" or quantum of electromagnetic radiation (EMR) which shows as individual lines in the spectrum. Where these lines are in the spectrum is characteristic of the type of atom that is emitting the EMR.

6. Apr 20, 2011

### chenesai

how do we get to the equation power= -2/3*e2*a2/c3 (two thirds*e squared*a squared all divided by c cubed
e is electron charge
a acceleration , equal to v squared for velocity over r for radius

7. Apr 20, 2011

### chenesai

how do we get to the equation power= -2/3*e2*a2/c3 (two thirds*e squared*a squared all divided by c cubed
e is electron charge
a acceleration , equal to v squared for velocity over r for radius