Question

Magnetic potential energy of a needle is minimum when the angle between the magnetic moment and magnetic field is

Answer 1

When angle is 90 b/w the magnetic field and magnetic moment, magnetic potential energy of a needle is minimum.

Explanation:

We know,

U= -m.B = -mBcosx

Where m is magnetic moment

B is magnetic field

Cosx is /_ b/w m and B

X=90°

U=-m.Bcosx

=-m.Bcos90°

=-m.B×0

= 0

U=0

Which is minimum magnetic potential energy