A short bar magnet with its axis at 30 degree to an external magnetic field of 800G experience a torque of 0.016Nm. Find the (i) magnetic moment of magnet (ii) Work done in turning the dipole from its stable to unstable position.
T = m B sin30
0.016 N = m 800 *10 -4*(1/2)
m= 0.016*2/8*10-2.
m= 1.6*2/8= 0.4 Am2.