A current carrying loop is placed in a uniform magnetic field in four different orientations , I,ii,iii & iv arrange them in the decreasing order of potential Energy`

Options

A. `IgtIIIgtIIgtIV`
B. `IgtIIgtIIgtIV`
C. `IgtIVgtIIgtIII`
D. `IIIgtIVgtIgtII`

Answer

A

Explanation

`P.E.` for magnetic dipole is
`u_(1)=MB [theta=-180^(@)]`
`u_(II)=0 [theta=90^(@)]`
`u_(III)=-Mbcostheta [0ltcosthetalt1]`
`u_(IV)=Mbcostheta [0 lt cos theta lt 1]`
`:.` Decreasing order of potential energy is,
`(IgtIVgtIIgtIII)`