The magnetic potential due to a magnetic dipole at a point on its axis situated at a distance of $20 \mathrm{~cm}$ from its center is $1.5 \times 10^{-5} \  \mathrm{Tm}$. The magnetic moment of the dipole is___________ $\mathrm{Am}^2$. (Given : $\frac{\mu_0}{4 \pi}=10^{-7} \  \mathrm{TmA}^{-1}$ )

Two identical bar magnets are fixed with their centres at a distance $d$ apart. A stationary charge $Q$ is placed at $P$ in between the gap of the two magnets at a distance $D$ from the center $O$ as shown in the figure. The force on the charge $Q$ is

Two short magnets of equal dipole moments $M $ are fastened perpendicularly at their centre (figure). The magnitude of the magnetic field at a distance $d $ from the centre on the bisector of the right angle is

Two magnets, each of magnetic moment $‘M’ $ are placed so as to form a cross at right angles to each other. The magnetic moment of the system will be

Two identical bar magnets with a length $10 \,cm $ and weight $50 \,gm$-weight are arranged freely with their like poles facing in a inverted vertical glass tube. The upper magnet hangs in the air above the lower one so that the distance between the nearest pole of the magnet is $3\,mm.$ Pole strength of the poles of each magnet will be.......$ amp × m$

The unit of magnetic moment is