Direction of Magnetic Field in Parallel Wires

In summary, when current flows in the same direction in two wires, the magnetic field between the wires is in the same direction. If current flows in opposite directions, the magnetic field between the wires is in opposite directions.
  • #1
decamij
53
0
If you have two parallel wires, each producing a magnetic field, what would the direction of the magentic field be if:
1) Current flowed in the same direction in each wire.
2) Current flowed in opposite direction in each wire.
 
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  • #2
Do you know how a magnetic field around a current carrying wire looks like? What direction are the field lines? Do you know what the force on a currnet carrying wire in a magnetic field is? What is the direction of this force?
 
  • #3
Right hand rule! Point the thumb of your right hand in the direction of current in the wire and your fingers curl around the wire in the direction of the field lines. What happens between the wires when the current is in the same direction? In opposite directions?
 
  • #4
When the current is in the same directions, the magentic field between the wires are in different directions. I know that the magnitude of magnetic field will decrease relative to if the current was in different directions, but what do I say for direction? I know about the right hand rule, but how do word the direction? Into/out of the page? Away from the wires? I'm not sure.
 
  • #5
Now you know what the magnetic fieldswill look like all you have to know is what is the direction of the force on a wire in a given magnetic field.
 
  • #6
If you know the direction and magnitude of the force on each wire, you use vectors to determine the net direction, right?
 
  • #7
The force on a charged particle in a magnetic field is given by the Lorentz force law: [tex]\vec{F}=q(\vec{v} \times \vec{B})[/tex]

Now current is flowing charge right? And qv is in the direction of the current! With this information, and some knowledge of the cross product (right hand rule, or corkscrew rule), you should be able to figure out the direction of the force.
 
  • #8
To know the DIRECTION of the force, all U have to do is:
1) use the right hand rule (quoted below). No fancy formulae are required.
2) use this hand rule: right hand open, fingers straight out, thumb to the right. Fingers (except the thumb) point in the direction of the magnetic field, thumb points in the direction of the moving POSITIVE charge (convertional current) and palm of hand points in the direction of the force.

HallsofIvy said:
Right hand rule! Point the thumb of your right hand in the direction of current in the wire and your fingers curl around the wire in the direction of the field lines. What happens between the wires when the current is in the same direction? In opposite directions?
 
  • #9
But if you don't know the direction of the current, just that they are in the same or different directions on each wire, how do u know the general direction? i.e. in what way will the magnetic fields "interfere" with each other, and what would the net electric field be?
 
  • #10
decamij said:
But if you don't know the direction of the current, just that they are in the same or different directions on each wire, how do u know the general direction? i.e. in what way will the magnetic fields "interfere" with each other, and what would the net electric field be?

Just draw a picture, in your head or on paper of a current carrying wire with trhe direction of its current Now find out what the magentic field will look like. Draw another wire parallel carrying current in the same or opposite direction. Now what is the direction of the force? You know the direction of the magentic field at the place of the second wire, and you know the driection of the current its carrying. I'm sure you can work it out!
 

1. What is the direction of the magnetic field in parallel wires?

The direction of the magnetic field in parallel wires is perpendicular to the direction of the current flow in the wires.

2. How does the direction of the current affect the direction of the magnetic field in parallel wires?

The direction of the current determines the direction of the magnetic field. If the current is flowing in the same direction in both wires, the magnetic field will be in the same direction. If the current is flowing in opposite directions, the magnetic field will be in opposite directions.

3. How do I determine the direction of the magnetic field in parallel wires?

You can use the right-hand rule to determine the direction of the magnetic field. Point your thumb in the direction of the current flow and your fingers will curl in the direction of the magnetic field.

4. Can the direction of the magnetic field be reversed in parallel wires?

Yes, the direction of the magnetic field can be reversed by reversing the direction of the current flow in the wires.

5. How does the distance between parallel wires affect the direction of the magnetic field?

The closer the wires are to each other, the stronger the magnetic field will be. However, the direction of the magnetic field will not be affected by the distance between the wires.

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