A bar magnet of length $10 \,cm$ and having the pole strength equal to $10^{-3}$ weber is kept in a magnetic field having magnetic induction $ (B)$ equal to $4\pi \times {10^{ - 3}}$ Tesla. It makes an angle of $30°$ with the direction of magnetic induction. The value of the torque acting on the magnet is
$2\pi \times {10^{ - 7}}\,N \times m$
$2\pi \times {10^{ - 5}}\,N \times m$
$0.5\,N \times m$
$0.5 \times {10^2}\,N \times m$
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 similar bar magnets $P $ and $Q$ , each of magnetic moment $M,$ are taken, If $P$ is cut along its axial line and $Q$ is cut along its equatorial line, all the four pieces obtained have
A short bar magnet with its north pole facing north forms a neutral point at $P$ in the horizontal plane. If the magnet is rotated by $90^o$ in the horizontal plane, the net magnetic induction at $P$ is (Horizontal component of earth’s magnetic field = ${B_H}$)
Give the explanation of Gauss’s law for magnetic field.
A bar magnet is cut into two equal parts then which of the following quantity may change
$(a)$ Intensity of magnetization
$(b)$ Pole strength
$(c)$ Magnetic moment