How to find direction of mangetic field created by current

In summary, direction of the magnetic field created by a toroid can be determined using the hand rule, which states that the direction of the field is perpendicular to the direction of the current and can be found by wrapping your hand around the toroid with your thumb pointing in the direction of the current. This direction can be different inside and outside the coil. Symmetry arguments do not address direction, but rather the uniformity of the field around the loop.
  • #1
sparkle123
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how to find direction of magnetic field created by toroid

I don't understand how to find the direction of B resulting from a toroid. In the following example from my textbook, the direction of B is found by symmetry arguments are used. (I highlighted this in yellow). Could someone please explain?
Thanks!

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  • #2
The symmetry argument does not address direction; it merely means the field is the same all around the loop because rotating the loop a few degrees does not change the situation.

The direction is determined by the hand rule. This page has it in the very first diagram:
http://hyperphysics.phy-astr.gsu.edu/hbase/magnetic/magfie.html#c1
I urge you to find a piece of wire and make a toroid. Then choose a spot on it and wrap your hand around it with your thumb in the direction of the current. Your fingers indicate the direction of the B field. It will go one way inside the coil, the opposite way outside it.
 
  • #3
Thanks! :)
 

FAQ: How to find direction of mangetic field created by current

How can I determine the direction of a magnetic field created by a current?

The direction of a magnetic field created by a current can be determined using the right-hand rule. Imagine holding your right hand with your thumb pointing in the direction of the current and your fingers curled towards the direction of the magnetic field. Your fingers will then point in the direction of the magnetic field.

Is there a formula for calculating the direction of a magnetic field created by a current?

Yes, the direction of a magnetic field created by a current can be calculated using the right-hand rule or using the cross product formula B = I x L, where B is the magnetic field, I is the current, and L is the length of the conductor.

Can the direction of a magnetic field created by a current change?

Yes, the direction of a magnetic field created by a current can change if the direction of the current or the position of the conductor is altered. It can also change if the strength of the current or the magnetic field is varied.

How do I determine the direction of a magnetic field if the current is moving in a circular path?

If the current is moving in a circular path, the direction of the magnetic field will be perpendicular to the path of the current, following the right-hand rule. The direction can also be determined using the cross product formula, where the direction will be perpendicular to both the current and the radius of the circular path.

Can I use a compass to determine the direction of a magnetic field created by a current?

Yes, a compass can be used to determine the direction of a magnetic field created by a current. The north pole of the compass will point towards the direction of the magnetic field. However, this method may not be accurate if the current is weak or the magnetic field is not strong enough to affect the needle of the compass.

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