Question

The substances which are attracted towards a magnet are called _______.
A. Metals
B. Ferro-magnetic materials
C. Non-metals
D. Dia-magnetic materials

Answer 1

Hint: Let us recall that metals are further classified on the basis of their magnetic properties into ferromagnetic, dia-magnetic, and paramagnetic materials. Magnetic susceptibility is a measure of how strong the magnetic property of a particular material is.

Complete answer:
We can call any material or object that has the property to produce a magnetic field, a magnet.
Let us discuss the magnetic properties of the above given options one by one.
Without a second thought we could strike out non-metals from the list, because it is a known fact that non-metals lack magnetic properties. Now comes metals, we cannot say that all metals show magnetic property. There comes a further classification based on the internal structure of materials as, ferromagnetic, paramagnetic, and dia-magnetic. In order to discuss their magnetic property, we need to know about magnetic susceptibility, ‘$\chi $ ’.
‘$\chi $’, is the measure of how a magnetic material responds to an external magnetic field. ‘$\chi $’, is negative for a dia-magnetic substance, it is small and positive for paramagnetic materials and is large and positive for ferromagnetic materials.
Among the three, dia-magnetic ones show slight repulsion when placed near a magnet, and paramagnetic materials do get attracted to magnets but very weakly.
Now, we are left with ferromagnetic materials which are considered as truly magnetic materials. They are the ones that get strongly attracted to magnets.
Hence, the answer to the given question is ferromagnetic materials.

So, the correct answer is “Option B”.

Additional Information:
Examples of magnetic metals are: iron, nickel, cobalt, steel, some of the stainless steels, and some rare earth metals like Gadolinium, Samarium, Neodymium.
There exists a classification of magnets. They are: permanent, temporary, and electromagnets. Permanent magnets (made of ferromagnetic materials) are known to be stable against demagnetising forces, that is, they do not stop producing magnetic fields regardless of any external influence. Temporary magnets only retain their magnetic property under certain conditions. Electromagnets show magnetic property when an electric current is passed through them.

Note:
We should remember that not all metals show magnetic property. There are metals like gold, silver, etc that lack magnetic property. Magnetite, an oxide of iron, shows ferrimagnetic property. However, the ferrimagnets lose magnetic properties above the Curie temperature and are weaker than ferromagnets.