Register to reply 
Biot–Savart law: the origin of chirality? 
Share this thread: 
#1
Jul1514, 07:20 AM

P: 53

As we know BiotSavart law follows righthand rule, like this:
...so the question is why righthand rule, why not left? I suppose it must have something to do with electron's magnetic dipole moment or "spin", as that's the only source of asymmetry I am aware of in this scenario. It follows then the orientation of the spin axis could be what defines this magnetic rotational direction, which would imply then the spin axis orientation is defined by the velocity vector. But still, the question remains, how or why could velocity vector have any specific directional impact on either intrinsic electron spin axis orientation or BiotSavart magnetic field rotation? 


#2
Jul1614, 03:28 PM

PF Gold
P: 1,141

The righthand rule works because it gives the same direction as the vector product in the BiotSavart law:
$$ \mathbf j(\mathbf x') \times \mathbf x  \mathbf x' $$ where ##\mathbf j## is current density at point ##\mathbf x'##, ##\mathbf x## is point where the magnetic field is sought. The vector product chooses one direction for ##\mathbf B## from two possibilities. Direction of magnetic field could have been defined to be opposite. Then we would use left hand to get this opposite direction. 


#3
Jul1614, 08:13 PM

Sci Advisor
P: 2,660

People use the right hand rule mostly because most people are right handed. It's easier to figure out the convention using the dominant hand. One can arbitrarily reverse all the fields and go by the left hand rule. The only physical effect is the motion of particles and forces on these particles inside these fields, so however direction you choose to define the fields is arbitrary as long as you get the motion correct in the end.



#4
Jul1914, 07:48 AM

Mentor
P: 16,947

Biot–Savart law: the origin of chirality?



Register to reply 
Related Discussions  
Biotsavart law  Advanced Physics Homework  10  
BiotSavart law  Classical Physics  1  
Biotsavart law  Introductory Physics Homework  20  
Biot Savart's Law  General Physics  2  
Biot Savart again  Classical Physics  2 