## angular momentum

1. The problem statement, all variables and given/known data
a classical electron moves in a circle of radius 0.5mm with velocity 20ms-1
what is the value of the quantum number L which gives a quantised angular momentum close to the angular momentum of this classical electron?

2. Relevant equations

L=r * p

3. The attempt at a solution

L=r*p
500e-6 * 20=0.010
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 You need to throw in the equation for quantum angular momentum.
 is it L=$\sqrt{l(l+1)hbar}$

## angular momentum

is it possible to find the value of the quantum number "l" (azimuthal quantum number)?
 Check the dimensions in that formula.
 do i have to presume that n=1 before i continue the calculation, because there is no mention of principal quantum number in the question?
 The description says "classical electron". So I guess you should use Bohr's model here. What is the angular momentum in Bohr's model?
 the lowest value for n is 1, this gives the smallest orbital radius 0.0529nm(bohr radius) L=r*p=mvr m=9.1e-31, v=20m/s r=0.5nm mvr=nhbar L=n h/2pi=nhbar
 I think you should use the latter formula to determine n that gives the closest match of L to that of the classical electron.
 can you explain that again please
 You can compute the angular momentum from the radius and velocity given. You have the formula for the angular momentum in Bohr's model. What n gives the closest fit between the two? You could also consider the other formula, involving the square root of l(l + 1). For large n, and correspondingly large l, what can be said about the results given by these two equations?

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