A magnetic needle of negligible breadth and thickness compared to its length, oscillates in a horizontal plane with a period $T$. The period of oscillation of each part obtained on breaking the magnet into $n$ equal parts perpendicular to the length is

A short bar magnet of magnetic movement $5.25 \times 10^{-2} \;J\, T ^{-1}$ is placed with its axis perpendicular to the earth's field direction. At what distance from the centre of the magnet, the resultant field is inclined at $45^{\circ}$ with earth's field on

$(a)$ its normal bisector and

$(b)$ its axis.

Magnitude of the earth's field at the place is given to be $0.42 \;G$. Ignore the length of the magnet in comparison to the distances involved.

A bar magnet of magnetic moment $M$ is cut into two parts of equal length. The magnetic moment of each part will be ......... $M$

Draw field lines on a bar magnet, a current carrying finite solenoid and electric dipole.

Two identical magnetic dipoles of magnetic moments $1.0 \,A-m^2$ each, placed at a separation of $2\,m$  with their axis perpendicular to each other. The resultant magnetic field at a point midway between the dipoles is

Magnetic moments of two bar magnets may be compared with the help of