A bar magnet having a magnetic moment of 2 × 10⁴ J T⁻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:

Question

Dr. Abubacker · Accepted Answer

[Solution from source] Work = MB(cos 0° − cos 60°) = 2 × 10⁴ × 6 × 10⁻⁴ × ½ = 6 J. The value 12 J is MB itself, which would be the work only for a 90° turn. Answer (2).

Q. A bar magnet having a magnetic moment of 2 × 10⁴ J T⁻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:

Explanation

Reviewed by Dr. Abubacker

Want to attempt the full paper?