An element `dvecl=dxhati` (where `dx=1cm`) is placed at the origin and carries a large current `i=10A`. What is the magnetic field on the Y-axis at a distance of `0.5m`?

Explanation

From Biot-Savart's Law, `|bar(d beta)| = 1 dl sin theta//r^2`
`dI = Delta x = 1 cm = 10^(-2) m, I = 10 A, r= y = 0.5 m`
`mu_(0)/ 4pi = 10^(-7) Tm//A, theta = 90^@` so sin `theta=1`
`|bar(d B)| = (10^(-7) xx 10xx10^(-2))/(25 xx 10^(-2)) = 4 xx 10^(-8)` T along + z axis