Two points $A$ and $B$ are situated at a distance $x$ and $2x$ respectively from the nearer pole of a magnet $2 \ cm$ long. The ratio of the magnetic field at $A$ and $B$ is

Verify Ampere's law for the magnetic field of a point dipole with dipole moment $\vec{M} = M\hat{k}$. Take $C$ as the closed curve running clockwise along the $z$-axis from $z = a > 0$ to $z = R$,then along the circular arc of radius $R$ to the $x$-axis,then along the $x$-axis to $x = a$,and finally along the circular arc of radius $a$ back to the $z$-axis.

$A$ magnetic needle is kept in a non-uniform magnetic field. It experiences

$A$ straight steel wire of length $\ell$ has a magnetic moment $M$. It is bent into an $L$-shape as shown in the figure. The new magnetic moment is

$A$ bar magnet of length $l$ and magnetic dipole moment $M$ is bent in the form of an arc as shown in the figure. The new magnetic dipole moment will be

Two lines of force due to a bar magnet: