Sir you are the best physics professor I've ever had. It's a shame your videos don't have as many views and likes as they should. I posted a comment about you on a PatrickJMT video, he is the guy I go to for math and he is really famous on youtube. I really hope more people can benefit from your videos in the future. Your website is very organized and your videos are great. You should include the website in the description for people who don't know about it. Thanks a lot for doing this
Consider this hypothetical scenario: suppose I have a wire with a cross section that is mapped out using the function y=f(x) with a uniform current density through it, how do I find B at an arbitrary distance away from the cross section?
Hi guys! at the time 8:46, I can not understand what is the lower r(r). Is it whole cable's radius or small loop's radius? Is there anybody who can explain it?
It is the radius of the small loop (the Amperian Loop). The right side of Ampere's equation, integral of B dot dl, is always referring to the Amperian Loop. The dl's always make up the Amperian Loop.
You don't really need to use current density (J) in this example because you know a current (I) is moving through the wire. You could use I = J*Pi*r^2 but its extra complication as I is known but J is not (so you would find J from I then substitute J in for I).
Think of this as a coaxial cable, which is made up of two conductors separated by some dielectric. The reason that the current, i, are in opposite directions is partly arbitrary but is based in application. He hinted at it with the sum of currents at a junctions being equal to zero ( just think of it as one being a propagating path and one being a return path).
with an off center cylindrical hole, the B field will not be same on the amperian loop (since the conductor will be closer to one side) thus the B will be not be constant and you will have a different answer.
Don't really get why you would replace I by J.A because you're adding more variables and only removing one constant (pi). But I guess it all depends on what you use the formula for.
Think of this as a coaxial cable, which is made up of two conductors separated by some dielectric. The reason that the current, i, are in opposite directions is partly arbitrary but is based in application. He hinted at it with the sum of currents at a junctions being equal to zero ( just think of it as one being a propagating path and one being a return path).
Sir you are the best physics professor I've ever had. It's a shame your videos don't have as many views and likes as they should. I posted a comment about you on a PatrickJMT video, he is the guy I go to for math and he is really famous on youtube. I really hope more people can benefit from your videos in the future. Your website is very organized and your videos are great. You should include the website in the description for people who don't know about it.
Thanks a lot for doing this
Phew! Now I can sleep better at night knowing the magnetic field outside my cable wire is 0. Thanks alot ;)
This channel saved my grade. Thank you so much, teacher. I got a B, when I could have gotten a D or even failed.
You have opened my third eye. Seriously thank you, you have saved my life for my emag exam
u r simply ..awesome..sir
keep on going....make us knowledge ful
Thank you very much for every good videos, teacher.
Thank you for your efforts and awesome videos and the way you explain the involved math so much easier to comprehend.
Learned so much from this! Thank you!
I know for a fact this guy has a mustache
How ?
@@kriscurkovic9265 shadow
Thanks Sr !! I´ll continuos watching your videos! thanks a lot
Consider this hypothetical scenario: suppose I have a wire with a cross section that is mapped out using the function y=f(x) with a uniform current density through it, how do I find B at an arbitrary distance away from the cross section?
Hi guys! at the time 8:46, I can not understand what is the lower r(r). Is it whole cable's radius or small loop's radius? Is there anybody who can explain it?
It is the radius of the small loop (the Amperian Loop). The right side of Ampere's equation, integral of B dot dl, is always referring to the Amperian Loop. The dl's always make up the Amperian Loop.
@@lasseviren1 Thanks Teacher :D. Hi from Turkey :D
thanks very very much. my exam is tomorrow and those videos helped me a lot!
you are the BEST, thank you for making these videos!
Why is B, the magnetic flux density, used as though it were H, the magnetic field intensity?
Thanks for the video. It helped me a lot with understanding the concept.
thank you. my teacher can't explain it like this at all
Please can someone tell me why in this case he doesn't replace I by J*PI*r^2 ?
You don't really need to use current density (J) in this example because you know a current (I) is moving through the wire. You could use I = J*Pi*r^2 but its extra complication as I is known but J is not (so you would find J from I then substitute J in for I).
can't pi.R^2.J be replaced by I since the inclosed current is equal to all the current through the wire?
+Jesper Fennema yes
I really like your videos, thank you
can u plz explain me why the current going in outer cylinder is opposite to that of inside ????
since its a junction....current entering junction=current leaving junction
Think of this as a coaxial cable, which is made up of two conductors
separated by some dielectric. The reason that the current, i, are in
opposite directions is partly arbitrary but is based in application. He
hinted at it with the sum of currents at a junctions being equal to zero
( just think of it as one being a propagating path and one being a
return path).
does the same apply for a copper conductor with an off center cylindrical hole?
with an off center cylindrical hole, the B field will not be same on the amperian loop (since the conductor will be closer to one side) thus the B will be not be constant and you will have a different answer.
Don't really get why you would replace I by J.A because you're adding more variables and only removing one constant (pi). But I guess it all depends on what you use the formula for.
Why is it that current goes down the sides? I didn't quite understand that.
Think of this as a coaxial cable, which is made up of two conductors separated by some dielectric. The reason that the current, i, are in opposite directions is partly arbitrary but is based in application. He hinted at it with the sum of currents at a junctions being equal to zero ( just think of it as one being a propagating path and one being a return path).
what does J stand for?
J is current density which is the current per cross-sectional area of the wire. J=I/Area and its units are A/m^2.
Thanks... useful stuff
soooooo good!!!
greeeeeeeat effort > Thanks a lot
.
You are awesome.
thank you! super cool :D
What’s J
I love you. Thanks
cool video; it'd be even cooler if you'd solve in terms of "I"
Thank you sir
agree !!!
I love you