# Spin (1 Viewer)

#### untouchablecuz

##### Active Member
i'm doing medical physics, but i thought i might get more responses here:

is spin a dimensionless quantity?
why must the spin of an elementary particle be a multiple of 1/2?
what is the difference between electronic spin and nuclear spin?

thanks

Last edited:

#### youngminii

##### Banned
Eww medical physics
Spin is a quantum number.. It's also a relativistic effect

What do you mean by 'dimensionless'? It's literally the spin - the rotation of a particle
I think it's way beyond the syllabus to ask why it's a multiple of 1/2
Electron spin is the 'original' spin. Nuclear spin applies to nucleons which have the same properties as electron spin.

Don't blame me if any of that's wrong
Beyond the syllabus anyways

#### untouchablecuz

##### Active Member
Eww medical physics
Spin is a quantum number.. It's also a relativistic effect

What do you mean by 'dimensionless'? It's literally the spin - the rotation of a particle
I think it's way beyond the syllabus to ask why it's a multiple of 1/2
Electron spin is the 'original' spin. Nuclear spin applies to nucleons which have the same properties as electron spin.

Don't blame me if any of that's wrong
Beyond the syllabus anyways
a dimensionless quanity is a quantity without physical units e.g. absorbance (with the AAS) is dimensionless

everywhere i see the spin of a nucleus, no units accompany it. so in other words, what are the units of spin?

also, what do you mean by the "original" spin? is that like the intrinsic spin of a particle?

some more Q's:

do electrons have "spin"? if so, how does this spin add to the overall spin of a nucleus?

even if its beyond the syllabus, could someone answer my Q's

thanks

#### Continuum

##### I'm squishy
is spin a dimensionless quantity?
why must the spin of an elementary particle be a multiple of 1/2?
what is the difference between electronic spin and nuclear spin?
Yeah, spin is a dimensionless quantity.

Spin is a multiple of 1/2 not because it was arbitrarily given it but because its an intrinsic property of the electron. Spin quantum number represents the angular momentum of the electron, and this happens to be half that of the angular momentum defined by its magnetic quantum number - hence why its a multiple of 1/2.

No idea for last one.

do electrons have "spin"? if so, how does this spin add to the overall spin of a nucleus?
Yeah, electrons have a 'spin' due to its angular momentum.

Again, no idea about the nuclear spin.

#### TheShepard256

##### New Member
do electrons have "spin"? if so, how does this spin add to the overall spin of a nucleus?
It doesn't, as the nucleus and electrons are separate parts of an atom. It does contribute to the total spin of the atom, and thus whether the atom acts as a fermion or a boson.