A bar magnet having a magnetic moment of 2× 104 JT-1 is

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A bar magnet having a magnetic moment of 2× 10⁴ JT^-1 is free to rotate in a horizontal plane. A horizontal magnetic field B = 6 × 10^-4 T exists in the space. The work done in taking the magnet slowly from a direction parallel to the field to a direction 60° from the field is

1. 12 J
2. 6 J
3. 2 J
4. 0.6 J

Correct Option: B

Work done
= MB (cos θ₁ – cos θ₂)
= MB (cos 0° – cos 60°)