Angular Variables

[Diego Zavala 2I]

We can state Heisenberg's Uncertainty Principle in terms of angular variable as , where delta L is the uncertainty in angular momentum and delta phi is the uncertainty in angular position. For electrons in an atom, the angular momentum has definite quantized values with no uncertainty whatsoever. What can we conclude about the uncertainty in the angular position and about the validity of the orbit concept?

[Diego Zavala 2I]

I manage to convert the equation in the textbook, delta X and delta momentum > h/4pi into
but I don't know how to interpret this equation given that angular momentum has no uncertainty.

[Humza_Khan_2J]

Angular momentum is based on velocity, ergo I would believe that it does have a level of uncertainty. However, there's a set angular momentum quantum number for each electron(but this determines shape). I believe these are two different concepts. Does anyone know more about a potential distinction between the two?

[Diego Zavala 2I]

I also thought that angular momentum should have some level of uncertainty, but I believe it does not because the problem states that angular momentum has definite qunatized values. However, the equation would not make sense since h would be divided by 0.