At a place where the magnitude of the earth's magnetic field is $4 \times 10^{-5} \mathrm{~T}$, a short bar magnet is placed with its axis perpendicular to the earth's magnetic field direction. If the resultant magnetic field at a point at a distance of 40 cm from the centre of the magnet on the normal bisector of the magnet is inclined at $45^{\circ}$ with the earth's field, then the magnele moment of the magnet is

Any magnetic material loses its magnetic property when it is

The domain in ferromagnetic material is in the form of a cube of side $2 \mu \mathrm{~m}$. Number of atoms in that domain is $9 \times 10^{10}$ and each atom has a dipole movement of $9 \times 10^{-24} \mathrm{Am}^2$. The magnetisation of the domain is (approximately).

A magnet suspended in a uniform magnetic field is heated, so as to reduce its magnetic moment by $19 \%$. By doing this, the time period of the magnet approximately