Question

The sure test of a magnet is:
(A) Magnetic attraction
(B) Magnetic Repulsion
(C) Both (a) and (b)
(D) None of these

Answer 1

Hint: A magnet attracts all ferromagnetic materials as well as magnets. A ferromagnetic material can be turned into a magnet by placing it on a magnetic field, this orients all the small magnetic domains present in it parallel to that of the original magnet.

Complete step by step solution:
It is known that similar poles of two magnets repel each other while the opposite poles attract. But a magnet can also attract other non-magnets, which include ferromagnetic materials like iron, cobalt and nickel.
The magnetic field lines arise from the north pole of the magnet and it ends on the south pole of the magnet. These magnetic field lines are present outside, around the magnet body and always form closed loops. The density of these lines defines the strength of the magnetic field.
When two field lines travel in the same direction their intensity adds up. But when they travel in opposite directions, the intensity tries to cancel out, this is why when two similar poles are brought close to each other, they repel.
When a ferromagnetic material is brought close to a magnet, it is temporarily magnetised by the field, thus is attracted by the magnet. It can never be repelled by a magnet.
When another magnet is brought close to a magnet, both of them have their own magnetic fields, so they attract when the field lines add up, or when the opposite poles are brought together. And they repel when the magnetic field lines have opposite directions and try to cancel each other, this happens when the similar poles are brought together.
Thus only repulsion between a magnet and an object can prove if the object is also a magnet.

Option (B) is correct.

Note: The polarity of a magnet can be efficiently explained by the concept of magnetic field lines, according to this, every magnet has two poles namely north and the south. Non-magnets can never be repelled by a magnetic field.