The effective length of a magnet is $ 31.4 \,cm $ and its pole strength is $0.5\, Am$. The magnetic moment, if it is bent in the form of a semicircle will be…..$A{m^2}$

Magnetic intensity for an axial point due to a short bar magnet of magnetic moment $M$ is given by

Write a brief history of magnet.

Two identical short bar magnets are placed at $120^{\circ}$ as shown in the figure. The magnetic moment of each magnet is $M$. Then the magnetic field at the point $P$ on the angle bisector is given by

Points $A$ and $B$  are situated along the extended axis of $2\, cm$  long bar magnet at a distance $x $ and $2x$ $ cm$  respectively. From the pole nearer to the points, the ratio of the magnetic field at $ A$ and $B$ will be