A bar magnet is placed in the position of stable equilibrium in a uniform magnetic field of induction B. If it is rotated through an angle if 90°, then the work is (M= magnetic dipole moment of bar magnet )

Question

A bar magnet is placed in the position of stable equilibrium in a uniform magnetic field of induction B. If it is rotated through an angle if 90°, then the work is (M= magnetic dipole moment of bar magnet ) (A) M B (B) 2 M B (C) (M B/2) (D) Zero

Tardigrade Admin · Accepted Answer

Work done, W=M B( cos θ1- cos θ2) Then, W=M B( cos 0°- cos 90°)=M B

Q. A bar magnet is placed in the position of stable equilibrium in a uniform magnetic field of induction $B$ . If it is rotated through an angle if $9 0^{\circ},$ then the work is $(M =$ magnetic dipole moment of bar magnet $)$

$MB$

$2 MB$

$\frac{MB}{2}$

Zero

Work done, $W = MB (cos θ_{1} - cos θ_{2})$
Then, $W = MB (cos 0^{\circ} - cos 9 0^{\circ}) = MB$

Q. A bar magnet is placed in the position of stable equilibrium in a uniform magnetic field of induction B. If it is rotated through an angle if 90∘, then the work is (M= magnetic dipole moment of bar magnet )

MB

2MB

2MB​