A short magnet placed with its axis making an angle with a uniform external magnetic field of induction `B` experiences a torque `(tau)`. If the magnet is free to rotate, which orientation would correspong to its stable and unstable equilibrium.

Options

A. `theta=0^(@),theta=90^(@)`
B. `theta=0^(@),theta=180^(@)`
C. `theta=45^(@),theta=135^(@)`
D. `theta=0^(@),theta=270^(@)`

Answer

B

Explanation

In stable equlibrium `PE` is minimum and in unstable equilibrium `PE` is maximum and `tau` is zero in both causes