A particle carrying a charge equal to $100$ times the charge on an electron is rotating per second in a circular path of radius $0.8$ $metre$. The value of the magnetic field produced at the centre will be $({\mu _0} = $ permeability for vacuum)

Show magnetic field lines due to current carrying loop.

A length $L$ of wire carries a steady current $I$. It is bent first to form a circular plane coil of one turn. The same length is now bent more sharply to give a double loop of smaller radius. The magnetic field at the centre caused by the same current is

Find the magnitude of magnetic field at point $p$ due to a semi - infinite wire given below

A circular loop of radius $r$ is carrying current I A. The ratio of magnetic field at the centre of circular loop and at a distance $r$ from the center of the loop on its axis is:

$B _{ X }$ and $B _{ Y }$ are the magnetic field at the centre of two coils of two coils $X$ and $Y$ respectively, each carrying equal current. If coil $X$ has $200$ turns and $20 cm$ radius and coil $Y$ has $400$ turns and $20 cm$ radius, the ratio of $B _{ X }$ and $B _{ Y }$ is