The force between two identical bar magnets whose centres are $r \ m$ apart is $4.8 \ N$,when their axes are in the same line. If the separation is increased to $2r$,the force between them is reduced to . . . . . . $N$.

The name 'magnet' came from which island?

$A$ magnetised wire of magnetic moment $3.14 \, A-m^2$ is bent in the form of a semi-circle. The new magnetic moment will be.....$A-m^2$

$A$ magnetized wire of magnetic moment $M$ and length $l$ is bent in the form of a semicircle of radius $r$. Then its new magnetic moment is:

Three identical bar magnets each of magnetic moment $M$ are placed in the form of an equilateral triangle as shown. The net magnetic moment of the system 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.