Considering `theta=pi//2` as the zero-energy position of a current loop of magnetic moment m placed in a magnetic field of strength B,find the minimum potential energy. In what position is the potential energy minimum? Is this an equilibrium position ? What will be the work done in turning it through `alpha` from this position ? Examine whether you get the dame position for equilibrium and same value for work if `theta=0` is taken as the zero-energy position.

Answer

`-mB` when `theta=0` , i.e. , coil phane is perpendicular to B yes, because `tau=0` in this position ; `mB(1-"coa"alpha)`