Question

If a magnetic dipole of moment M situated in the direction of a magnetic field B is rotated by \(180^\circ\), then the amount of work done is

• A. \(MB\)
• B. \(2 MB\)
• C. \(\frac{MB}{\sqrt{2}}\)
• D. \(0\)
• E. \(\sqrt{MB}\)

Hint:

Rotating a dipole from stable equilibrium (\(0^\circ\)) to unstable equilibrium (\(180^\circ\)) requires the maximum amount of work, which is exactly \(2 MB\). If rotated only to \(90^\circ\), the work would be \(MB\).

Answer 1

The Correct Option is B