Consider the situation shown in the diagram, where A small magnetised needle A is placed at a centre marked, as O. The direction of its mangetic moment I s indicated by arrow. The other arrow show different position (and orientations of the magnetic moment) of antoher identical magnetised eedle X.
In which configuration the system is not in equlibrium?
(ii) In which configuration is the system in (a) stable and (b) unsable equilibrium
(iii) Which configuration corresponds to the lowest potentials energy among all the configuration shown

Options

A. `PQ_(3)`
B. `PQ_(4)`
C. `PQ_(5)`
D. `PQ_(6)`

Answer

D

Explanation

As P and `Q_(6)` is parallel i.e., `theta= 0^(@)`
`U_("min")= - MB cos theta= - MB`