Magnetism and Matter

Iron is ferromagnetic :
Which one of the following substances is the magnetic substance ?
Which of the following is not a component of electric bell?
The magnetic susceptibility of a paramagnetic substance at $$-173^o$$C is $$1.5\times 10^{-2}$$ then its value at $$-73^o$$C will be.

When a bar magnet is placed perpendicular to a uniform a magnetic field, it is acted upon by a couple of magnitude $$1.732\times 10^{-5}Nm$$. The angle through which the magnet should be turned so that the couple acting on it becomes $$1.5\times 10^{-5}Nm$$ is