Finding the Direction of Magnetic Fields with Opposing Currents

In summary, to find the direction of the magnetic field at a point, you can use the right-hand rule and apply it separately to each current, then combine the results. Remember that fields add as vectors and the diagram is symmetric except for the directions of the currents. It may seem like the two currents cancel each other out, but when you consider the rotation of your hand, it becomes clear that they are all in the positive x direction.
  • #1
PolarBee
14
1

Homework Statement


33.Ex13_v2.jpg

How do I find the direction of the magnetic field at the points?

Homework Equations



Ampere's B = (UI) / (2*pi*r)[/B]

The Attempt at a Solution



I know how the Right hand rule, where your thumb is the direction of the current and your hand wraps the direction of the field, but I'm not sure how it plays in when both the current are opposite.
 
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  • #2
Try applying the right-hand rule to each of the currents separately and combining the results. Remember that fields add as vectors. and that the diagram is symmetric except for the directions of the currents.
 
  • #3
John Park said:
Try applying the right-hand rule to each of the currents separately and combining the results. Remember that fields add as vectors. and that the diagram is symmetric except for the directions of the currents.
Yes , but aren't they equal and opposite? Wouldn't they just cancel each other?
 
  • #4
Have you tried it? Start with point (b). For the upper current your thumb points towards you and your fingers are under your hand. For the lower current your thumb points away from you and your fingers are above your hand . . .
 
  • #5
John Park said:
Have you tried it? Start with point (b). For the upper current your thumb points towards you and your fingers are under your hand. For the lower current your thumb points away from you and your fingers are above your hand . . .
Oh I see~ I was taking into consideration of of the whole rotation of my hand, so the back of my hand should face wherever the point is? So they're all in the positive x direction?
 
  • #6
looks that way to me.
 

What is the direction of a magnetic field?

The direction of a magnetic field is the direction in which a compass needle would point at any given point in space. It is also the direction of the force that a moving charged particle would experience if placed in that magnetic field.

How is the direction of a magnetic field determined?

The direction of a magnetic field is determined by the right-hand rule. This rule states that if you point your thumb in the direction of the current in a wire, your fingers will wrap around in the direction of the magnetic field.

Can the direction of a magnetic field change?

Yes, the direction of a magnetic field can change. It can change due to the movement of charged particles, such as in an electromagnet. It can also change due to the Earth's magnetic field shifting over time.

What is the difference between a north and south magnetic pole?

The north and south magnetic poles are the two ends of a magnet. The north pole of a magnet is attracted to the south pole of another magnet, while the north pole of a magnet is repelled by the north pole of another magnet. This is due to the alignment of the magnetic domains within the magnet.

How is the direction of a magnetic field related to electricity?

The direction of a magnetic field is closely related to electricity. Moving electrical charges, or current, create magnetic fields. Similarly, a changing magnetic field can induce an electrical current in a conductor. This relationship is described by Maxwell's equations.

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