An element $d l=d x \hat{l}$ (where, $d x=1\, cm$ ) is placed at the origin and carries a large current $i=10 A$. What is the magnetic field on the $Y$ -axis at a distance of $0.5\, m$ ?

The earth's magnetic induction at a certain point is $7 \times {10^{ - 5}}\,Wb/{m^2}.$ This is to be annulled by the magnetic induction at the centre of a circular conducting loop of radius $5 \,cm$. The required current in the loop is......$A$

Magnetic field intensity at the centre of coil of $50$ $turns$, radius $0.5\, m$ and carrying a current of $2\, A$ is

A regular polygon of $6$ sides is formed by bending

a wire of length $4 \pi$ meter. If an electric current of $4 \pi \sqrt{3} \mathrm{~A}$ is flowing through the sides of the polygon, the magnetic field at the centre of the polygon would be $x \times 10^{7} \mathrm{~T}$. The value of $\mathrm{x}$ is______.

A charge $q$ coulomb moves in a circle at $n$ revolutions per second and the radius of the circle is $r$ metre; then magnetic field at the centre of the circle is

The magnetic field at the origin due to the current flowing in the wire is