Question about the right hand rule

In summary, the conversation discusses the use of the right hand rule in finding the direction of the force in a conductor when the magnetic field is at an angle other than 90 degrees from the current. The participants also mention different versions of the right hand rule and provide a resource for further understanding.
  • #1
Josh123
30
0
Hello.

I have a question about RHR #2 (Force in a conductor).

If IL X B = F and
If the fingers represent the direction of the current, the thumb represents the direction of the force and the palm is the direction of the magnetic field, how come the magnetic field can be at an angle other than 90 degrees from IL? In such a case, does the RHR still apply? For example, how would I find the direction of the force on side A (Bottom wire ) in this case:

http://img.photobucket.com/albums/v228/LianaBlank/untitled.bmp

B is on the positve X direction (palm)... but IL is at 60 degrees from B.. How do I use my Right Hand rule to find F?
 
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  • #2
Josh123 said:
Hello.

I have a question about RHR #2 (Force in a conductor).

If IL X B = F and
If the fingers represent the direction of the current, the thumb represents the direction of the force and the palm is the direction of the magnetic field, how come the magnetic field can be at an angle other than 90 degrees from IL? In such a case, does the RHR still apply? For example, how would I find the direction of the force on side A (Bottom wire ) in this case:

http://img.photobucket.com/albums/v228/LianaBlank/untitled.bmp

B is on the positve X direction (palm)... but IL is at 60 degrees from B.. How do I use my Right Hand rule to find F?


"palm" is the problem. B is not in the direction of the palm. The palm is merely the direction toward which you must curl your fingers to get from the direction of L to the direction of B through the smaller angle. That angle can be anywhere between 0 and 180 degrees
 
Last edited by a moderator:
  • #3
Josh123 said:
If IL X B = F and
If the fingers represent the direction of the current, the thumb represents the direction of the force and the palm is the direction of the magnetic field, how come the magnetic field can be at an angle other than 90 degrees from IL?
The magnetic field can be anywhere it wants to be with respect to IL, of course. But F will always turn out to be 90 degrees from both IL and B.
In such a case, does the RHR still apply? ...
B is on the positve X direction (palm)... but IL is at 60 degrees from B.. How do I use my Right Hand rule to find F?
Sure the right hand rule applies. It may be easiest to just consider the component of IL perpendicular to B (and ignore the component parallel to B, since it will create no force!).
 
  • #4
OlderDan said:
"palm" is the problem. B is not in the direction of the palm. The palm is merely the direction toward which you must curl your fingers to get from the direction of L to the direction of B through the smaller angle. That angle can be anywhere between 0 and 180 degrees
I'm glad you mentioned that Dan (I was just going to myself).

The "right hand rule" that I use is the one that Dan describes. To find [itex]\vec{A}\times\vec{B}[/itex], I "curl" my fingers from A to B... my thumb indicates the direction of the cross-product.

(There are several versions of the right hand rule; some are better than others. :smile: )
 
  • #6
Thanks Doc... I'll check it out
 

1. What is the right hand rule?

The right hand rule is a commonly used mnemonic device in physics and engineering to determine the direction of a magnetic field, current, or force in relation to a wire or moving charge. It involves pointing the thumb of your right hand in the direction of the current or velocity, and curling your fingers towards the magnetic field or force.

2. How do I use the right hand rule?

To use the right hand rule, make a fist with your right hand and point your thumb in the direction of the current or velocity. Then, curl your fingers towards the magnetic field or force. The direction your fingers point in is the direction of the magnetic field or force.

3. What is the purpose of the right hand rule?

The right hand rule is used to determine the direction of a magnetic field, current, or force in relation to a wire or moving charge. It is a helpful tool in understanding and visualizing the interactions between electricity and magnetism.

4. Can the right hand rule be used for both electric and magnetic fields?

Yes, the right hand rule can be used for both electric and magnetic fields. For electric fields, the thumb points in the direction of the electric field and the fingers point in the direction of the force on a positive charge. For magnetic fields, the thumb points in the direction of the current or velocity and the fingers point in the direction of the magnetic field or force.

5. Are there any variations of the right hand rule?

Yes, there are variations of the right hand rule depending on the specific application. One example is the right hand thumb rule, where the thumb points in the direction of the force on a current-carrying wire in a magnetic field. Another variation is the right hand palm rule, where the palm of the hand is used to determine the direction of the force on a current-carrying wire in a magnetic field.

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