Hello miss ! These playlists are saving my grade so thank you very much but i had a small doubt around 22:34 . If we describe B=F/L what happened to the current ? Is it automatically presumed to be 1? Thank you in advance !
Something is wrong! On two levels (superposition and field considerations). But was is the CORRECT explanation? The Superposition Principle does not cancel out the entire field between the wires. If there is no magnetic field between the wires there can't be any repelling force between the wires right. Actually the fields do not cancel out between the wires. There is only one single point (or line) between the wires where the added field vectors are equal to zero, and that is in the exact middle of the wires (assuming that the current is equal and in the same direction in the two wires). All other places adding the field vectors will not be equal to zero. Assume that two wires carry the same amount of current running in the same direction. One wire will create a magnetic field into the page and the other wire will create a magnetic field out of the page (between the wires that is). Since magnetic fields obey the Superposition Principle and the current is equal in the two wires, the magnetic fields between the wires will cancel out right in the center between the wires (and only in center between the wires). The further away we get from a wire, the weaker the field gets. So close to wire 1 the field from that wire will be a lot stronger than the field from wire 2. The resulting field close to wire 2 will thus not point into the page because the strong field going out of the page caused by the current in wire 2, will swallow the weak field caused by the current in wire 1. The same goes in the other direction. So the resulting fields are actually the opposite of what is explained in this video (if the current in the two wires are equal and in the same direction). Close to wire 2 (between the wires) the field will go out of the page because the net field close to wire 2 is by far dominated by the field produced in wire 2. Close to wire 1 (between the wires) the field will go into the page because the net field close to wire 1is by far dominated by the field produced in wire 1. What is explained in this video is that the field will cancel out in the entire space between the wires resulting in a peanut shaped field. If this was the case then there would be no forces acting between the wires at all! Conclusion: This explanation is not correct. The two wires (equal current in the same direction) will actually attract each other in real life? How can we explain that?
Yepp that's correct, the fields can only completely cancel out (resultant = zero) at one position between the wires due to superposition of fields like this picture shows: d1yqpar94jqbqm.cloudfront.net/styles/media_full/s3/images/d9d4b194b7b970c2bec9edc9d1d8a92086a11288.jpg?itok=oT6KXmya
Other than the point of perfect cancellation where the B-field vectors are in equal magnitude and opposite direction, there would be varying degrees of "cancellation" in the regions between the wires - in comparison to the areas wrapping around both wires where the fields would "add". As to how the resultant field looks like, the peanut shape sketch here doesn't show the full details like what you mentioned 👍 If I we add more lines nearer to wire, it would look like this diagram: www.physics.louisville.edu/cldavis/phys111/notes/mag_2wires.gif You should look up the math of magnetic vector fields in spherical coordinate system (uni level), I think you'd enjoy it. 😉
Thank you. I agree that the image you linked to (mag_2wires.gif) is an good model of reality. The image shows the direction of the current going out of the page, and a magnetic field between the wires going up/north close to wire one (the left wire in the left picture) and a magnetic field between the wires going south/down close to wire two (the right wire in the left picture). This is correct because close to wire one on the line between the two wires, the weak field from wire two is eaten by the strong field from wire one. The same goes for wire two. So I think that we agree that the image (mag_2wires.gif) of the two wires carrying the same amount of current in the same direction (out of the page) is correct right? This i however not what you show in the video. Close to wire one you show the field from wire two (going down/south), and deduct that the field points towards wire two. Close to wire two you show the field from wire one (going up/north), and deduct that the field points towards wire one. What I'm saying is that this is not correct and the image you posted also shows the opposite of what you are saying. According to the image you posted (mag_2wires.gif) the forces should point away from the center and the wires should repel. In reality the wires actually attract each other just like you say (ua-cam.com/video/43AeuDvWc0k/v-deo.html), so what is wrong with the explanation? The answer is that the field (superimposed by the two fields) between the wires make the wires repel! However because some of the field cancels out between the wires, the fields on the outside of the wires will result in a larger force and dominate. Since these forces point towards the center of the wires the result is attraction! So actually we have four forces acting on the wires (looking at the straight line through the center of the wires). Wire one has a strong force pointing towards the center and a weaker force pointing away from the center. The same goes for wire two. F1 ------> O O
I cannot express how you are literally saving my future career, my teacher in physics is very unqualified and finding your UA-cam channel saved me 😭😭😭
i hope they update the playlists according to new syllabus
YIPIEIEIEIEIIEIE YAYAYAYAYAYYAYAYAYAY YAYYYYYYYY SUIIIIIIIIIIIIIIIIIIIII GOLAZOOOO IMMENSE. JazakAllah
Hello miss ! These playlists are saving my grade so thank you very much but i had a small doubt around 22:34 . If we describe B=F/L what happened to the current ? Is it automatically presumed to be 1? Thank you in advance !
Thank you that was so helpful
hello, is the equation to calculate force given in examination?
Check the Data Formulae sheet! If it's not there for the 2022 syllabus, them no :/
Something is wrong! On two levels (superposition and field considerations). But was is the CORRECT explanation?
The Superposition Principle does not cancel out the entire field between the wires. If there is no magnetic field between the wires there can't be any repelling force between the wires right.
Actually the fields do not cancel out between the wires. There is only one single point (or line) between the wires where the added field vectors are equal to zero, and that is in the exact middle of the wires (assuming that the current is equal and in the same direction in the two wires). All other places adding the field vectors will not be equal to zero.
Assume that two wires carry the same amount of current running in the same direction. One wire will create a magnetic field into the page and the other wire will create a magnetic field out of the page (between the wires that is). Since magnetic fields obey the Superposition Principle and the current is equal in the two wires, the magnetic fields between the wires will cancel out right in the center between the wires (and only in center between the wires). The further away we get from a wire, the weaker the field gets. So close to wire 1 the field from that wire will be a lot stronger than the field from wire 2. The resulting field close to wire 2 will thus not point into the page because the strong field going out of the page caused by the current in wire 2, will swallow the weak field caused by the current in wire 1.
The same goes in the other direction.
So the resulting fields are actually the opposite of what is explained in this video (if the current in the two wires are equal and in the same direction).
Close to wire 2 (between the wires) the field will go out of the page because the net field close to wire 2 is by far dominated by the field produced in wire 2.
Close to wire 1 (between the wires) the field will go into the page because the net field close to wire 1is by far dominated by the field produced in wire 1.
What is explained in this video is that the field will cancel out in the entire space between the wires resulting in a peanut shaped field. If this was the case then there would be no forces acting between the wires at all!
Conclusion: This explanation is not correct.
The two wires (equal current in the same direction) will actually attract each other in real life? How can we explain that?
Yepp that's correct, the fields can only completely cancel out (resultant = zero) at one position between the wires due to superposition of fields like this picture shows:
d1yqpar94jqbqm.cloudfront.net/styles/media_full/s3/images/d9d4b194b7b970c2bec9edc9d1d8a92086a11288.jpg?itok=oT6KXmya
Other than the point of perfect cancellation where the B-field vectors are in equal magnitude and opposite direction, there would be varying degrees of "cancellation" in the regions between the wires - in comparison to the areas wrapping around both wires where the fields would "add". As to how the resultant field looks like, the peanut shape sketch here doesn't show the full details like what you mentioned 👍
If I we add more lines nearer to wire, it would look like this diagram:
www.physics.louisville.edu/cldavis/phys111/notes/mag_2wires.gif
You should look up the math of magnetic vector fields in spherical coordinate system (uni level), I think you'd enjoy it. 😉
Thank you.
I agree that the image you linked to (mag_2wires.gif) is an good model of reality.
The image shows the direction of the current going out of the page, and a magnetic field between the wires going up/north close to wire one (the left wire in the left picture) and a magnetic field between the wires going south/down close to wire two (the right wire in the left picture). This is correct because close to wire one on the line between the two wires, the weak field from wire two is eaten by the strong field from wire one. The same goes for wire two. So I think that we agree that the image (mag_2wires.gif) of the two wires carrying the same amount of current in the same direction (out of the page) is correct right?
This i however not what you show in the video.
Close to wire one you show the field from wire two (going down/south), and deduct that the field points towards wire two.
Close to wire two you show the field from wire one (going up/north), and deduct that the field points towards wire one.
What I'm saying is that this is not correct and the image you posted also shows the opposite of what you are saying.
According to the image you posted (mag_2wires.gif) the forces should point away from the center and the wires should repel.
In reality the wires actually attract each other just like you say (ua-cam.com/video/43AeuDvWc0k/v-deo.html), so what is wrong with the explanation?
The answer is that the field (superimposed by the two fields) between the wires make the wires repel! However because some of the field cancels out between the wires, the fields on the outside of the wires will result in a larger force and dominate. Since these forces point towards the center of the wires the result is attraction!
So actually we have four forces acting on the wires (looking at the straight line through the center of the wires).
Wire one has a strong force pointing towards the center and a weaker force pointing away from the center.
The same goes for wire two.
F1 ------> O O
my bro literally wrote two essays 💀