Orbital and spin angular momentum

In summary, there is no single formula for both orbital and spin angular momentum. The formula J=mvr is used for orbital angular momentum in the classical sense, while quantum mechanically, there is no classical expression for spin angular momentum. The formula J=mvr can be used to calculate orbital angular momentum, such as the spin of the Earth, but for quantum objects, angular momentum and spin are not defined by the same formula. It is important to clarify what is meant by "spin" in order to determine the appropriate formula for calculating it.
  • #1
spidey
213
0
what are the formulas for orbital and spin angular momentum? Or both have the same formula?

The formula J=mvr is for orbital or spin angular momentum?
 
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  • #2
spin is not a derivable quantity in the sense if orbital angular momentum. So you can't have such a classical expression for it.

J=mvr is the orbital angular momentum, albeit in a the classical sense.

quantum mechanically one can't have such formulae. Its a bit different in this regime.
 
  • #3
vkroom said:
spin is not a derivable quantity in the sense if orbital angular momentum. So you can't have such a classical expression for it.

J=mvr is the orbital angular momentum, albeit in a the classical sense.

quantum mechanically one can't have such formulae. Its a bit different in this regime.

if J=mvr is the orbital angular momentum then how to calculate spin angular momentum..

for example,earth spins on its own axis so how to calculate Earth's spin angular momentum...some black holes also spin so how to calculate?
 
  • #4
dude, u shud be clear as to what you mean by spin.

if its the usual spin in physics, i.e. the one ppl talk abt in particles like electrons, then its not what u are writing here.
if its Earth's spinning rate u want to know, then its still the same old angular momentum, bt for something known as a "rigid body" rotation. its given as : L = Iw. wiki a bit and u'll be through.

angular momentum and spin for quantum object are not defined by such formula as mentioned above.
 

1. What is the difference between orbital and spin angular momentum?

Orbital angular momentum refers to the rotational motion of a particle around an axis, while spin angular momentum refers to the intrinsic angular momentum of a particle. In other words, orbital angular momentum is associated with the motion of an object in space, while spin angular momentum is an inherent property of a particle.

2. How are orbital and spin angular momentum related to each other?

Orbital and spin angular momentum are both forms of angular momentum and are related through the total angular momentum of a particle. The total angular momentum is the sum of the orbital and spin angular momentum.

3. How is orbital angular momentum quantized?

Orbital angular momentum is quantized, meaning it can only take on certain discrete values. This is due to the wave-like nature of particles and is governed by the laws of quantum mechanics. The quantization of orbital angular momentum is represented by the quantum number l.

4. What is the significance of spin angular momentum?

Spin angular momentum is a fundamental property of particles and is responsible for their magnetic properties. It also plays a crucial role in determining the electronic structure of atoms and the behavior of particles in magnetic fields.

5. How does orbital and spin angular momentum affect the behavior of an electron?

The combination of orbital and spin angular momentum determines the energy levels and allowed transitions of an electron in an atom. It also affects the magnetic properties and the behavior of the electron in an external magnetic field.

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