A magnetic needle suspended horizontally by an unspun silk fibre, oscillates in the horizontal plane because of the restoring force originating mainly from

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

Due to a small magnet intensity at a distance $x$ in the end on position is $9$ $Gauss$. What will be the intensity at a distance $\frac{x}{2}$ on broad side on position..... $Gauss$

Points $A$ and $B$ are situated perpendicular to the axis of a small bar magnet at large distances $x$ and $3 x$ from its centre on opposite sides. The ratio of the magnetic fields at $A$ and $B$ will be approximately equal to

A magnetic needle is kept in a non-uniform magnetic field. It experiences

Two bar magnets with magnetic moments $ 2 M $ and $M$ are fastened together at right angles to each other at their centres to form a crossed system, which can rotate freely about a vertical axis through the centre. The crossed system sets in earth’s magnetic field with magnet having magnetic moment $2M $ making and angle  $ \theta $ with the magnetic meridian such that