Answer key

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Last edited 26 days ago by Learn LoopHQ.

Chapter: 07. Magnetism

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A primary difference is that permanent magnets are usually made of steel, while temporary magnets are typically made of soft iron.

The process by which a magnetic material attains magnetism temporarily or permanently is called magnetisation.

One example of a natural magnet is magnetite, which is an iron ore also known as lodestone.

A soft-iron piece is typically used for the core of a temporary electromagnet.

When the north pole of one magnet is brought near the north pole of another magnet, they will repel each other, pushing away.

Animals like migratory birds utilize Earth’s magnetism as an internal compass for navigation during their long journeys.

The double touch method is a way of magnetising a magnetic material by rubbing two bar magnets of equal strength against it, moving them from the center outwards repeatedly.

No, magnetic lines of force never intersect each other because they repel each other.

William Gilbert was an English physician and physicist who discovered that the Earth itself acts as a giant magnet, which explains why a freely suspended magnet always aligns itself in the north-south direction.

The imaginary curved lines representing the magnetic field around a magnet are called magnetic lines of force.

Two common shapes of artificial magnets are the bar magnet and the horseshoe magnet.

The magnetic force is always maximum at the two ends of a magnet, which are known as its poles.

A freely suspended magnet always aligns itself in the geographic north-south direction.

An electromagnet can be made a permanent magnet if a piece of steel is used as the core instead of soft iron.

The Earth’s magnetic north pole is located near the geographic south pole.

Two examples of non-magnetic substances are paper and wood, as they are not attracted by magnets.

The property of attracting iron and other materials like steel, cobalt, and nickel is called magnetism.

Magnets are used in magnetic compasses for finding directions, in refrigerator doors for sealing, and in dynamos for generating electricity.

One action that can cause a magnet to lose its magnetic properties is dropping it frequently.

Repulsion is considered the surest test of magnetism because only a magnet will repel another magnet’s like pole, whereas attraction can occur between unlike poles or between a magnet and a non-magnetic material.

The soft iron pieces used to store magnets are called magnetic keepers.

When making a magnetic compass, the cork with the magnetised needle should be placed gently and centrally in the water tub to ensure it floats freely without obstruction.

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