Recent content by gsan

I don't know how to integral since it is very complicated.

An infinite current filament carries a current of 3A and lies along the x-axis. Using Biot-Savart Law, find the magnectic field intensity in cartesian coordinates at a point P(-1,3,2). dH = I vec{dl} x hat{R} / 4piR^2 let substitude hat{R} with vec{R} / R then dH = I vec{dl} x vec{R} / 4piR^3...

ya, I'm asked to integrate to find the field at that point

An infinite current filament carries a current of 3A and lies along the x-axis. Using Biot-Savart Law, find the magnectic field intensity in cartesian coordinates at a point P(-1,3,2). dH = I (vet)dl x hat{R} / 4piR^2 let say substitude hat{R} with (vet)R / R then dH = I (vet)dl x (vet)R /...

sorry, my mistake, let say the cable carry current lies along the x-axis, so vector of dl = hat{x} dx and vector of R = hat{x}3 + hat{y}2 + hat{z} 3 the cross product of vector of dl and vector of R |hat{x} hat{y} hat{z}| | 1 0 0 | | 3 2 3 | [ - hat{y}3 + hat{z}2 ]dx is my...

vector R = (unit vector R)(magnitude of R) and now my question is let say vector of dl = hat{x} dx and vector of R = hat{x}3 + hat{y}2 + hat{z} 3 the cross product of vector of dl and vector of R should be |hat{x} hat{y} hat{z}| | dx 0 0 | | 3 2 3 | or |hat{x} hat{y} hat{z}| | 1 0 0 | | 3...

let say vector of dl = hat{x} dl and vector of R = hat{x}3 + hat{y}2 + hat{z} 3 the cross product of vector of dl x vector of R should be |hat{x} hat{y} hat{z}| | dl 0 0 | | 3 2 3 | or |hat{x} hat{y} hat{z}| | 1 0 0 | | 3 2...

ok, I understand why unit vector of R has magnitude of 1. now my another question is, why we can cross product of a vector with a unit vector? eg. vector of dl x unit vector of R

how do u know the \hat{R} has magnitude of 1 ?

why the B=1 ? yes, I know that \vec{A}\times\vec{B} = AB\sin\theta

I not really understand about the 2nd formula, could explain more?

yes, I'm understand that dl is perpendicular to unit vector of R, but how the magnitude of them become dl only?

Refer to the attachment below, anyone can explain the formula highlighted by red box? how the | dl x R | become dl only?

@Defennder I m really confuse. what about for below example? http://img.photobucket.com/albums/v235/gsan_bot/magnetic2.jpg" if you say that Lenz law is -d(phi)/dt, then for this case, -d(phi)/dt should be less than zero, the flux is decreasing and the current should flow couterclockwise.

the direction flow of the current indicates that the induces B field oppose the increasing flux... but the d (magnetic flux linkage) / dt should be less than 0, so the induces B field must point into the plane and the direction of the current should be flow from left to right, right?