Why Do Magnetic Fields Differ in Right Hand Rule Illustrations?

[WardenOfTheMint]

Homework Statement

http://www.cramster.com/Answer-Board/Image/20073231626286331026398833900007956.jpg

This is not problem. I just having trouble understanding the basics. Please just tell me right away, don't 'assist!'

I trying to understand the right hand rule. Here are to images I found to illustrate my problem. Apparently, right hand rule 2 tells you to grip a long wire, and to find the magnetic field from that. Okay so if I grip a wire with current going upwards, the magnetic field is into the page, and if the current is going downwards, then magnetic field is out of the page.

But you do you explain these two picture?
In the first picture, the magnetic field is on the 5A wire is apparently ...downwards? How? And the magnetic field on the 3A wire is downward? How is that work? First they don't tell you which way the current is going, up or down. Secondly, the answer is not 'into the page' or 'out of the 'page.' It is 'upwards' or 'downwards,' how come?

The second image is mind baffling. What is going on? How can two wires coming out the page have different magnetic fields?

 

[alphysicist]

Homework Statement

http://www.cramster.com/Answer-Board/Image/20073231626286331026398833900007956.jpg

This is not problem. I just having trouble understanding the basics. Please just tell me right away, don't 'assist!'

I trying to understand the right hand rule. Here are to images I found to illustrate my problem. Apparently, right hand rule 2 tells you to grip a long wire, and to find the magnetic field from that. Okay so if I grip a wire with current going upwards, the magnetic field is into the page, and if the current is going downwards, then magnetic field is out of the page.

I'm not sure what you mean by these statements, but they don't sound right, and I think they are the source of your confusion. A wire does not have a single direction of the magnetic field; the magnetic field direction depends on what point you're talking about.

If a current is going upwards (towards the top of a page), the magnetic field is not simply "into the page". The current creates a magnetic field everywhere; at points to the right of the current is is into the page; to the left of the current it is out of the page; behind the current it is to the left; in front of the current it is to the right. (At other points it is at an angle.)

If you hold your right hand with the thumb upwards and rotate your hand around the thumb, you can see these directions are indicated by your fingers as you move your hand around (with your thumb always kept pointing upwards).


So if you look at your first figure, the question is not,"What is the direction of the magnetic field of the 5A wire?" because there's not enough information given to get a specific direction.

Instead, What is the direction of the magnetic field of the 5A wire at point P? What is the direction of the magnetic field of the 5A wire at the position of the 3A wire? Those two questions have different answers. Do you see what the answers are?

 

[baba89]

I can provide an explanation for the right hand rule and the images you have provided. The right hand rule is a way to determine the direction of the magnetic field created by a current-carrying wire. It is based on the principle that the magnetic field lines around a wire are circular and perpendicular to the direction of the current.

In the first image, the direction of the magnetic field is determined by the direction of the current in the wire. As you correctly stated, if the current is going upwards, the magnetic field will be into the page. However, if the current is going downwards, the magnetic field will be out of the page. This is because the direction of the magnetic field is always perpendicular to the direction of the current.

In the second image, the two wires are coming out of the page, but they have different directions of current. This means that the magnetic fields around them will also be in different directions. The direction of the magnetic field is determined by the direction of the current, not the direction of the wire itself.

It is important to note that the right hand rule is just a tool to determine the direction of the magnetic field. It does not tell us the strength of the field, which is determined by other factors such as the distance from the wire and the amount of current.

I hope this explanation helps you better understand the right hand rule and how it applies to these images. If you have any further questions, please do not hesitate to ask.