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Exploring Magnets - Attraction and Repulsion between Magnets

Grade 6CBSE

Review the key concepts, formulae, and examples before starting your quiz.

🔑Concepts

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Every magnet, regardless of its shape, has two poles: the North Pole (NN) and the South Pole (SS).

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Magnetic poles always exist in pairs; they cannot be isolated. Even if a magnet is broken, each piece will have its own NN and SS poles.

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The Law of Magnetism states that like poles (North-North or South-South) repel each other, while unlike poles (North-South) attract each other.

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A freely suspended bar magnet always comes to rest in the North-South direction. The end pointing towards the geographic North is the North-seeking pole (NN).

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Repulsion is the only 'sure test' for magnetism. This is because a magnet can attract both an opposite pole and a non-magnetized magnetic material (like iron), but it can only repel another magnet's like pole.

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Magnetic force is a non-contact force, meaning magnets do not need to touch to exert attraction or repulsion on each other.

📐Formulae

Like Poles  ⟹  Repulsion(N↔N or S↔S)\text{Like Poles} \implies \text{Repulsion} \quad (N \leftrightarrow N \text{ or } S \leftrightarrow S)

Unlike Poles  ⟹  Attraction(N→←S)\text{Unlike Poles} \implies \text{Attraction} \quad (N \rightarrow \leftarrow S)

💡Examples

Problem 1:

If two magnets are placed such that the South pole (SS) of the first magnet faces the South pole (SS) of the second magnet, describe the resulting interaction.

Solution:

The two magnets will push each other away (Repulsion).

Explanation:

According to the fundamental law of magnetism, like poles repel each other. Since both poles are South (SS), they exert a repulsive force.

Problem 2:

You are given two identical-looking metal bars, AA and BB. One is a magnet and the other is a simple iron bar. How can you identify the magnet using only these two bars?

Solution:

Bring one end of bar AA near both ends of bar BB. If both ends of BB are attracted to AA, then AA is the magnet and BB is iron. If one end of BB is repelled, then both are magnets.

Explanation:

Magnets attract magnetic materials like iron from both ends. However, two magnets will show repulsion when like poles face each other. Since repulsion only occurs between two magnets, it is the definitive test.

Problem 3:

A student suspends a bar magnet using a thread. In which direction will the magnet point when it comes to rest?

Solution:

The magnet will align itself in the North-South direction.

Explanation:

The Earth behaves like a giant magnet. A freely suspended magnet aligns itself with the Earth's magnetic field, with its North pole (NN) pointing toward the Earth's geographic North pole.