Direction of the magnetic field

[Cici2017]

Homework Statement

Homework Equations

The Attempt at a Solution

I know if the currents are going the same direction they attract. So the top 2 attract each other and the bottom two attraction each other? And then the top repel the bottom...
I'm stuck, please help~

 

[Doc Al]

I know if the currents are going the same direction they attract. So the top 2 attract each other and the bottom two attraction each other?

Don't worry about the forces the wires exert on each other. You are asked to find the field at point P. What's the field from a current-carrying wire?

 

[Cici2017]

Don't worry about the forces the wires exert on each other. You are asked to find the field at point P. What's the field from a current-carrying wire?

Magnetic field?

 

[Doc Al]

Magnetic field?

Yes. So how do you find the magnetic field surrounding a current-carrying wire?

 

[Cici2017]

B=F/ILsinθ
The direction is determined by right hand rule?
mmm...I don't know, what do I do next?

 

[Doc Al]

B=F/ILsinθ

Wrong formula. Again, you are not finding the force on a current-carrying wire, but the field surrounding it.

Read this: Magnetic Field of Current

The direction is determined by right hand rule?

Yes! Read the above link.