Magnetic field

[chiddler]

---

Members don't see this ad.

Big picture.

i hope i'm not just doing the right hand rule incorrectly, but it seems that if both are going in opposite directions then their magnetic fields add up. The answer suggests the opposite, that if they go in the same direction then the magnetic fields add up.

Answer is D:

"From the RHR, we know that the magnetic field is generated in the same direction when the currents are in the same direction. We know that the closer the wire is to the point in question, the greater the field strength. The smaller circles are closer and thus generate a stronger electric field. D has the strongest combination of the choices."

Also, i'd like to know why they put a straight line down the middle if it doesn't represent a current.

Thanks.

 

[milski]

If the currents are rotating in the same direction, the fields will pointed in the same direction as well. How did you manage to twist your hand so that the magnetic fields cancel?

For example, in C both magnetic fields are pointed up. If you're thinking that it's up above the current loop and down below it, that's the source of your confusion. The source of the field is not the center of the loop - the field is just a vector pointed up that goes through that center.

I don't understand the question about the straight line at the end - you'll have to elaborate more.

 

[SaintJude]

The straight line is just an "artifact". They are trying to designate a line of axis to clarify which rings have smaller or bigger radii.

 

[milski]

The straight line is just an "artifact". They are trying to designate a line of axis to clarify which rings have smaller or bigger radii.

I don't see them. Unless you mean the "axis lines" which are there for orientation and don't seem to represent any physical objects.

 

[chiddler]

i'm trying to figure out how to draw out how i'm perceiving it...

 

[SaintJude]

I don't see them. Unless you mean the "axis lines" which are there for orientation and don't seem to represent any physical objects.

Yeah, that's exactly what I'm saying but...I couldn't as clearly as you did.

Chiddler, you're right! They should have never done that! They probably should have drawn a dashed line to follow typical conventions. But they also told you that the arrows represent the direction of the current.

 

[chiddler]

ok after redrawing it a bunch of times i see my error. i can't tell you guys what it is because i have no idea how to communicate it, but i understand 😛

thanks very much!

 

[chiddler]

Yeah, that's exactly what I'm saying but...I couldn't as clearly as you did.

Chiddler, you're right! They should have never done that! They probably should have drawn a dashed line to follow typical conventions. But they also told you that the arrows represent the direction of the current.

EK1001 questions are worded in a very....boring way. I have gotten so many questions wrong just because I skim the prefaces :-x

It is an unfamiliar drawing, but I should not have been as confused as I was. Yes, they did tell me. And this was my mistake.