Answer –
Moment of the bar magnet is given by M = 0.32 JT–1
External magnetic field, is given by B = 0.15 T
- The magnetic field is aligned with the bar magnet. This system is said to be in a state of stable equilibrium. As a result, the angle Θ between the bar magnet and the magnetic field is 0.
Potential energy of the system is given by –
\[-MB\cos \theta =-0.32\times 0.15\times \cos {{0}^{\bullet }}\]
\[=-4.8\times {{10}^{-2}}J\]
- In this case, the bar magnet is oriented at 180° to the magnetic field. Hence, it is in unstable equilibrium. Here , θ=180°
Potential energy of the system is given by –
\[-MB\cos \theta =-0.32\times 0.15\times \cos {{180}^{\bullet }}\]
\[=4.8\times {{10}^{-2}}J\]