- #1

referframe

Gold Member

- 298

- 13

As always, thanks in advance.

- I
- Thread starter referframe
- Start date

- #1

referframe

Gold Member

- 298

- 13

As always, thanks in advance.

- #2

gneill

Mentor

- 20,874

- 2,837

Before the electron even enters the region of the magnetic field it already possesses angular momentum about the future center of the circular arc.

- #3

A.T.

Science Advisor

- 10,709

- 2,298

As @gneill notes: It has angular momentum even when it's moving in a straight line, around any point not on that line.During the “turning” of the electron (a finite time interval), does it temporarily possess classical orbital angular momentum?

What exactly do you mean by "classical orbital angular momentum"? There is some abiguity:

https://en.wikipedia.org/wiki/Orbital_angular_momentum

- #4

Dale

Mentor

- 30,273

- 6,735

Yes, except that it is probably much less temporary than you might assume.During the “turning” of the electron (a finite time interval), does it temporarily possess classical orbital angular momentum?

- #5

- 44

- 18

Not exactly, although the distinction is a pedantic one to a certain degree in such a situation. It is still the case that one might measure the electron in a basis not commuting with Angular Momentum. Only if we have an experimental set up which can measure angular momentum can we then say (assuming the wave function is reasonably "tight" about a classical path) that it has orbital angular momentum.Before the electron even enters the region of the magnetic field it already possesses angular momentum about the future center of the circular arc

Last edited:

- #6

gneill

Mentor

- 20,874

- 2,837

Keep in mind that this problem is posed in a "Classical Physics" domain.Not exactly, although the distinction is a pedantic one to a certain degree in such a situation. It is still the case that one might measure the electron in a basis not commuting with Angular Momentum. Only if we have an experimental set up which can measure angular momentum can we then say (assuming the wave function is reasonably "tight" about a classical path) that it has orbital angular momentum.

- #7

- 44

- 18

Well if the electron is treated as a classical object then it definitely has orbital angular momentum. I thought usage of "Keep in mind that this problem is posed in a "Classical Physics" domain.

- #8

Dale

Mentor

- 30,273

- 6,735

I guess you missed the word “classical”. He is talking about a classical point charge, not an actual electron.one might measure the electron in a basis not commuting with Angular Momentum

- #9

gneill

Mentor

- 20,874

- 2,837

No harm, no foul. I frequently misinterpret intended situations until I stand back and look at the context.Well if the electron is treated as a classical object then it definitely has orbital angular momentum. I thought usage of "temporarily possess classicalorbital angular momentum" suggested the electron was being treated quantum mechanically.

- #10

referframe

Gold Member

- 298

- 13

Thanks, I forgot just how general the definition of classical angular momentum was.I'm not sure if there's any technical distinction between regular "angular momentum" and "orbital angular momentum", save that one is associated with an orbiting body.

Before the electron even enters the region of the magnetic field it already possesses angular momentum about the future center of the circular arc.

View attachment 256352

- Last Post

- Replies
- 2

- Views
- 1K

- Replies
- 5

- Views
- 3K

- Replies
- 12

- Views
- 1K

- Last Post

- Replies
- 2

- Views
- 1K

- Last Post

- Replies
- 4

- Views
- 1K

- Replies
- 4

- Views
- 924

- Replies
- 2

- Views
- 1K

- Last Post

- Replies
- 9

- Views
- 2K

- Last Post

- Replies
- 6

- Views
- 4K

- Last Post

- Replies
- 1

- Views
- 1K