Question

The work done in, deflecting a compass needle of magnetic moment M through an angle $ \theta $ from its equilibrium position is [ $ H= $ horizontal] component of the earths magnetic field

• A. $ MH\sin \theta $
• B. $ MHcos\theta $
• C. $ MH(1-\sin \theta ) $
• D. $ MH\,(1-\cos \theta ) $

Answer 1

Answer: (D)

Work done in deflecting the needle of magnetic moment M in magnetic field it $ W=MH\,(1-\cos \theta ) $