Olympiad Test: Fun With Magnets

Freely Suspended Magnet always points in the North-South direction even in the absence of any other magnet. This suggests that the Earth itself behaves as a magnet which causes a freely suspended magnet (or magnetic needle) to point always in a particular direction.

A natural magnet is a magnet that occurs naturally in nature. All natural magnets are permanent magnets, meaning they will never lose their magnetic power. Natural magnets can be found in sandy deposits in various parts of the world. The strongest natural magnet material is lodestone, also called magnetite.

Iron, cobalt and steel are ferromagnetic materials which can be used to make magnet but ebonite cannot be used to make magnets.

Iron, cobalt and nickel are magnetic materials.

A magnet attracts the steel pin. When the pin touches the magnet it can't attract it any closer and it sticks to the magnet. However, a magnet will attract a pin from a distance.

The poles of the magnet has more attraction of magnetic force. That is why pins stick ends of the magnet.

The earth behaves as a magnetic dipole . Therefore a freely suspended magnet always points towards in the north-south direction because the north pole of the suspended magnet attracts the south pole of the earth's magnet which is the geographical north pole of the earth.

The earth behaves as a magnetic dipole . Therefore a freely suspended magnet always points towards in the north-south direction because the south pole of the suspended magnet attracts the north pole of the earth's magnet which is the geographical south pole of the earth.

Like poles of two magnets repel each other, The force between them is non contact force and magnetic force.

Unlike poles of different magnets attract each other; like poles repel each other.

Repulsion is the surest test for magnetism.

Only magnets possess the repulsive characteristics, whereas any magnetic substance (like iron) has attractive characteristics.

If the north (N pole) of a bar magnet is brought near the N pole of another suspended magnet, the suspended magnet moves away.  Repulsion also occurs when two south poles (S poles) are brought near each other. 

A magnetic compass is an instrument used for navigation and orientation that shows direction relative to the geographic cardinal directions (or points). Usually, a diagram called a compass rose shows the directions north, south, east, and west on the compass face as abbreviated initials.

The correct option is D.
 Most permanent magnets can hold up to being dropped a few times, but it will lose strength from repeated strikes with a hammer.A magnet subjected to heat experiences a reduction in its magnetic field as the particles within the magnet are moving at an increasingly faster and more sporadic rate. This jumbling confuses and misaligns the magnetic domains, causing the magnetism to decrease.

The magnetic property of a compact disk may be damaged when a powerful magnet is kept near it. Plastic glass and wood are non-magnetic materials hence cannot be magnetised or demagnetised.

The correct answer is D as COMB does not get demagnetised when a powerful magnet is kept near it

An electric bell contains an electromagnet, consisting of coils of insulated wire wound round iron rods. When an electric current flows through the coils, the rods become magnetic and attract a piece of iron attached to a clapper. The clapper hits the bell and makes it ring.

An electromagnet is a type of magnet in which the magnetic field is produced by an electric current. The magnetic field disappears when the current is turned off. Electromagnets usually consist of wire wound into a coil.

Magnetic fields are produced by moving electric charges. Everything is made up of atoms, and each atom has a nucleus made of neutrons and protons with electrons that orbit around the nucleus. Since the orbiting electrons ≠are tiny moving charges, a small magnetic field is created around each atom.