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Chapter 4. Exploring Magnets

Chapter Review

Chapter 4. Exploring Magnets

Magnets have fascinated people for thousands of years because of their unique ability to attract certain materials without touching them. Today, magnets are used in everyday objects such as refrigerator doors, speakers, toys, electric motors, mobile phones, magnetic compasses, and many scientific instruments. In this chapter, you will learn about magnetic and non-magnetic materials, the poles and properties of magnets, how magnets help us find directions, the working of a magnetic compass, attraction and repulsion between magnets, and the proper care and uses of magnets. Understanding these concepts helps us appreciate the important role magnets play in science and technology. :contentReference[oaicite:0]{index=0}

Chapter Review

Introduction to Magnets

A magnet is a special object that can attract certain materials such as iron, nickel, cobalt, and some of their alloys. This attractive force is called magnetism. Magnets can pull magnetic materials even without direct contact, making them different from ordinary objects. Magnets are available in many shapes such as bar magnets, horseshoe (U-shaped) magnets, ring magnets, and disc magnets, each designed for different purposes.

Magnetic and Non-Magnetic Materials

Not every material is attracted by a magnet. Based on this property, materials are classified into two groups.

Magnetic Materials

• Iron
• Nickel
• Cobalt
• Some alloys containing these metals

These materials are attracted towards a magnet and can also be separated from non-magnetic materials using magnets.

Non-Magnetic Materials

• Wood
• Plastic
• Glass
• Rubber
• Paper
• Cloth

These materials are not attracted towards magnets and remain unaffected by magnetic force. :contentReference[oaicite:2]{index=2}

Poles of a Magnet

Every magnet has two ends known as the North Pole and the South Pole. These ends are called the poles of the magnet. Iron filings gather mostly near the poles because the magnetic force is strongest there.

One important fact is that a magnet can never have only one pole. Even if a magnet is broken into smaller pieces, each piece will always have both a North Pole and a South Pole.

• Every magnet has two poles.
• Magnetic force is strongest at the poles.
• A single magnetic pole cannot exist.

This property makes magnets different from many other objects. :contentReference[oaicite:3]{index=3}

Properties of Magnets

Magnets possess several unique properties that make them useful in daily life.

• Magnets attract magnetic materials.
• They have two poles.
• Magnetic force is maximum at the poles.
• A freely suspended magnet always points in the north-south direction.
• Magnets can attract certain objects without touching them.
• Magnetic force can pass through several non-magnetic materials.

These properties form the basis of many scientific instruments and electrical devices.

Finding Directions Using Magnets

One of the most useful properties of a magnet is that when it is suspended freely, it always comes to rest in the north-south direction. The end pointing towards the north is called the North Pole, while the opposite end is the South Pole.

This happens because the Earth itself behaves like a giant magnet. This property has helped travellers and sailors find directions for centuries before modern navigation systems were developed. :contentReference[oaicite:5]{index=5}

Magnetic Compass

A magnetic compass is an important device used to determine directions. It contains a small magnetized needle that rotates freely. After some time, the needle aligns itself along the north-south direction.

Parts of a Magnetic Compass

• Magnetized needle
• Pivot or pin
• Circular dial
• Transparent cover

Uses of a Compass

• Finding directions
• Navigation by sailors
• Trekking and camping
• Survey work

Modern magnetic compasses work on the same principle discovered many centuries ago. :contentReference[oaicite:6]{index=6}

Making a Simple Magnetic Compass

A simple compass can be prepared by rubbing a sewing needle with one pole of a bar magnet several times. The needle becomes magnetized and is then passed through a cork and floated on water. After some time, it comes to rest in the north-south direction, acting as a simple compass.

Ancient Indians used a similar navigation device called the Matsya Yantra. :contentReference[oaicite:7]{index=7}

Attraction and Repulsion Between Magnets

When two magnets are brought close together, they may either attract or repel each other depending on the poles facing each other.

Pole Combination	Result
North – North	Repulsion
South – South	Repulsion
North – South	Attraction
South – North	Attraction

Repulsion is considered the surest test of a magnet because ordinary iron is always attracted but never repels a magnet.

Magnetic Effect Through Non-Magnetic Materials

Magnetic force can pass through several non-magnetic materials such as wood, plastic, cardboard, and glass. Even when these materials are placed between a magnet and a compass needle, the needle still shows deflection.

This proves that magnetic force does not always require direct contact between the magnet and the object.

Uses of Magnets

Magnets are widely used in homes, schools, industries, and scientific research.

• Magnetic compass
• Refrigerator doors
• Pencil boxes
• Door catches
• Speakers and microphones
• Electric motors
• Toys
• Maglev trains
• Medical equipment

Because magnets can produce force without touching objects, they are extremely useful in modern technology.

Care of Magnets

Magnets lose their strength if they are not handled properly. Therefore, they should be stored carefully.

• Do not heat magnets.
• Do not hammer or drop magnets.
• Keep magnets away from electronic devices.
• Store bar magnets in pairs with unlike poles together.
• Place a wooden strip between the magnets.
• Use soft iron keepers across their ends.

Proper storage helps magnets retain their magnetic strength for a longer period. :contentReference[oaicite:11]{index=11}

Important Terms

• Magnet
• Magnetism
• Magnetic Materials
• Non-Magnetic Materials
• North Pole
• South Pole
• Magnetic Compass
• Attraction
• Repulsion
• Magnetic Force
• Earth's Magnetism
• Matsya Yantra

Quick Revision

• Magnets attract magnetic materials such as iron, nickel, and cobalt.
• Wood, plastic, glass, and rubber are non-magnetic materials.
• Every magnet has two poles—North and South.
• The magnetic force is strongest at the poles.
• A single magnetic pole cannot exist.
• A freely suspended magnet always points in the north-south direction.
• The Earth behaves like a giant magnet.
• A magnetic compass is used to find directions.
• Unlike poles attract each other, whereas like poles repel each other.
• Repulsion is the surest test of a magnet.
• Magnetic force can pass through wood, glass, plastic, and cardboard.
• Magnets are widely used in homes, industries, medicine, and transportation.
• Magnets should never be heated, hammered, or dropped.
• Store magnets properly to preserve their magnetic strength.

Chapter 4. Exploring Magnets

NCERT Text Book Questions With Answers

Chapter 4. Exploring Magnets

The NCERT Textbook Exercise helps students revise the important concepts covered in the chapter. The following questions and answers are prepared in simple and easy-to-understand language according to the latest NCERT Curiosity textbook and CBSE guidelines. Students are advised to attempt each question on their own before checking the answers.

NCERT Textbook Exercise

Question 1. Fill in the blanks.

(i) Unlike poles of two magnets attract each other, whereas like poles repel each other.

(ii) The materials that are attracted towards a magnet are called magnetic materials.

(iii) The needle of a magnetic compass rests along the north-south direction.

(iv) A magnet always has two poles.

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Question 2. State whether the following statements are True (T) or False (F).

(i) A magnet can be broken into pieces to obtain a single pole.

Answer: False

(ii) Similar poles of a magnet repel each other.

Answer: True

(iii) Iron filings mostly stick in the middle of a bar magnet when it is brought near them.

Answer: False

(iv) A freely suspended bar magnet always aligns with the north-south direction.

Answer: True

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Question 3. Column I shows different positions in which one pole of a magnet is placed near that of the other. Column II indicates the resulting interaction between them. Fill in the blanks.

Column I	Column II
N – N	Repulsion
N – S	Attraction
S – N	Attraction
S – S	Repulsion

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Question 4. Atharv rolled a bar magnet over a heap of steel U-clips. At which position will the magnet attract the maximum number of U-clips?

Answer:

The maximum number of steel U-clips will stick near the two ends (poles) of the bar magnet because the magnetic force is strongest at the poles. Therefore, the correct observation is Option (i), where Positions A and C attract the maximum number of clips, while the middle position attracts fewer clips.

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Question 5. Reshma bought three identical metal bars. Two were magnets and one was an ordinary iron bar. Without using any other material, how can she identify the two magnets?

Answer:

Bring one end of each bar near the ends of the other bars. If two bars show repulsion between similar poles, then both are magnets. The ordinary iron bar will always be attracted by a magnet and will never repel it. Therefore, the two bars that repel each other are the magnets.

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Question 6. You are given a magnet whose poles are not marked. How can you identify its poles using another magnet with marked poles?

Answer:

Bring the known North Pole of the marked magnet close to one end of the unmarked magnet.

• If they repel each other, that end is the North Pole.
• If they attract each other, that end is the South Pole.

Similarly, the other end can also be identified.

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Question 7. A bar magnet has no markings to indicate its poles. How would you find out which end is the North Pole without using another magnet?

Answer:

Suspend the bar magnet freely using a thread tied at its centre. Allow it to come to rest. The end that always points towards the geographic north is the North Pole, while the opposite end is the South Pole.

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Question 8. If the Earth itself is a magnet, can you identify the magnetic poles of the Earth by observing a magnetic compass?

Answer:

Yes. The north-seeking end of a compass needle points towards the Earth's geographic north. This indicates that the Earth behaves like a giant magnet. The magnetic poles of the Earth are located close to its geographic poles, allowing the compass to indicate directions.

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Question 9. While repairing a gadget, a mechanic found that steel screws kept falling from the screwdriver. Suggest a solution based on what you have learnt in this chapter.

Answer:

The mechanic should magnetise the tip of the screwdriver by rubbing it several times in one direction with one pole of a bar magnet. The magnetised screwdriver will hold the steel screws firmly, making the repair work easier.

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Question 10. Two ring magnets X and Y are arranged one above the other. Magnet X does not move down further. What is the reason? Suggest a way to bring magnet X in contact with magnet Y without pushing either magnet.

Answer:

The facing poles of magnets X and Y are like poles, so they repel each other. This magnetic repulsion prevents magnet X from moving downward.

To bring magnet X into contact with magnet Y, simply turn either one of the ring magnets upside down. Unlike poles will then face each other and the magnets will attract, allowing magnet X to move down and touch magnet Y.

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Question 11. Three magnets are arranged as shown in the figure. The polarity of one end (5) is given as North. Determine the polarity at the remaining ends (1, 2, 3, 4, and 6).

Answer:

• 1 – South (S)
• 2 – North (N)
• 3 – South (S)
• 4 – North (N)
• 6 – South (S)

This is because every magnet always has one North Pole and one South Pole, and the arrangement follows the rules of magnetic attraction and repulsion.

Chapter 4. Exploring Magnets

Extra Questions Examination Based

Chapter 4. Exploring Magnets

The following important questions are designed according to the latest CBSE pattern and NCERT Curiosity textbook. These questions cover all the important concepts of the chapter and help students strengthen their understanding while preparing for school examinations.

Important Questions with Answers

Students should first try to answer these questions on their own and then compare their answers with the solutions given below.

1 Mark Questions

Question 1. What is a magnet?

Answer: A magnet is an object that attracts magnetic materials such as iron, nickel, and cobalt.

Question 2. Name any two magnetic materials.

Answer: Iron and nickel.

Question 3. Name two non-magnetic materials.

Answer: Wood and plastic.

Question 4. How many poles does a magnet have?

Answer: A magnet has two poles.

Question 5. Which pole of a freely suspended magnet points towards the north?

Answer: The North Pole.

Question 6. Which instrument is used to find directions?

Answer: A magnetic compass.

Question 7. Which poles of two magnets attract each other?

Answer: Unlike poles attract each other.

Question 8. Which poles repel each other?

Answer: Like poles repel each other.

Question 9. Where is the magnetic force strongest in a magnet?

Answer: At the poles of the magnet.

Question 10. Can a single magnetic pole exist independently?

Answer: No, a single magnetic pole cannot exist independently.

2 Marks Questions

Question 1. Differentiate between magnetic and non-magnetic materials.

Answer:

• Magnetic materials are attracted by magnets.
• Non-magnetic materials are not attracted by magnets.
• Examples of magnetic materials are iron and cobalt.
• Examples of non-magnetic materials are wood and plastic.

Question 2. Why are the poles of a magnet important?

Answer:

• The poles are the strongest parts of a magnet.
• Most magnetic attraction occurs at the poles.
• They determine attraction and repulsion between magnets.

Question 3. How does a magnetic compass help us?

Answer:

• It helps us find directions.
• Its needle aligns in the north-south direction.
• It is useful for navigation and travelling.

Question 4. Why is repulsion considered the surest test of a magnet?

Answer:

• Iron is always attracted by a magnet.
• Only another magnet can repel a magnet.
• Therefore, repulsion confirms that the object is a magnet.

Question 5. Write any four uses of magnets.

Answer:

• Magnetic compass
• Refrigerator doors
• Electric motors
• Speakers and headphones

3 Marks Questions

Question 1. Explain the properties of magnets.

Answer:

• Magnets attract magnetic materials.
• Every magnet has two poles.
• Like poles repel and unlike poles attract.
• A freely suspended magnet points in the north-south direction.
• Magnetic force is strongest at the poles.

Question 2. Describe how to make a simple magnetic compass.

Answer:

• Magnetise a sewing needle by rubbing it with one pole of a magnet.
• Pass the needle through a cork.
• Float it on water.
• The needle settles in the north-south direction.

Question 3. Explain attraction and repulsion between magnets.

Answer:

• Unlike poles attract each other.
• Like poles repel each other.
• Repulsion is the surest test of a magnet.
• These properties help identify the poles of magnets.

Question 4. Why should magnets be stored carefully?

Answer:

• Heating reduces magnetic strength.
• Hammering damages magnets.
• Dropping magnets weakens them.
• Proper storage helps retain magnetism for a long time.

Question 5. Explain why the Earth is called a giant magnet.

Answer:

• A freely suspended magnet always points north-south.
• This happens because of Earth's magnetic field.
• The Earth behaves like a giant magnet.
• Its magnetic field helps a compass show directions.

Long Answer Questions

Question 1. Explain the different types of magnetic and non-magnetic materials with suitable examples.

Answer:

Materials attracted by magnets are called magnetic materials. Iron, nickel, cobalt, and some of their alloys belong to this group. These materials are used in making machines, tools, and electrical appliances. Materials such as wood, plastic, glass, rubber, paper, and cloth are not attracted by magnets and are called non-magnetic materials. Magnets help in separating magnetic materials from non-magnetic ones in industries and recycling processes.

Question 2. Describe the important properties of magnets.

Answer:

Magnets attract magnetic materials and possess two poles known as the North Pole and South Pole. The magnetic force is strongest at the poles. Like poles repel each other, while unlike poles attract each other. A freely suspended magnet always aligns itself in the north-south direction because the Earth behaves like a giant magnet. Magnets can also exert force through several non-magnetic materials such as paper, wood, plastic, and glass.

Question 3. Explain the construction and working of a magnetic compass.

Answer:

A magnetic compass contains a small magnetised needle mounted on a pivot so that it can rotate freely. When kept on a level surface, the needle aligns itself in the north-south direction under the influence of the Earth's magnetic field. The north-seeking end of the needle points towards the geographic north. Magnetic compasses are widely used for navigation, trekking, surveying, and locating directions.

Question 4. Write the uses and care of magnets.

Answer:

Magnets are used in refrigerator doors, speakers, microphones, electric motors, magnetic compasses, toys, cranes, medical equipment, and many electronic devices. To maintain their magnetic strength, magnets should not be heated, hammered, or dropped. They should be stored properly using soft iron keepers and kept away from electronic gadgets.

Question 5. Explain how magnets help us in our daily life.

Answer:

Magnets play an important role in everyday life. They help us find directions using a compass, keep refrigerator doors closed, operate electric motors and generators, produce sound in speakers and headphones, separate iron objects from waste materials, and are used in many household appliances and scientific instruments. Without magnets, many modern technologies would not function efficiently.

Chapter 4. Exploring Magnets

40 Important MCQs with Answers

Chapter 4. Exploring Magnets

The following Multiple Choice Questions (MCQs) are based on the latest NCERT Curiosity textbook and CBSE examination pattern. These questions cover all the important concepts of the chapter and help students prepare effectively for school examinations and competitive assessments.

40 Important MCQs with Answer Key

Question 1. A magnet attracts which of the following materials?

• (A) Plastic
• (B) Iron
• (C) Wood
• (D) Rubber

Question 2. Which of the following is a magnetic material?

• (A) Glass
• (B) Nickel
• (C) Paper
• (D) Cotton

Question 3. Which metal is NOT attracted by a magnet?

• (A) Iron
• (B) Cobalt
• (C) Aluminium
• (D) Nickel

Question 4. Every magnet has _____ poles.

• (A) One
• (B) Two
• (C) Three
• (D) Four

Question 5. The poles of a bar magnet are located at its _____.

• (A) Centre
• (B) Ends
• (C) Middle only
• (D) Surface only

Question 6. Magnetic force is strongest at the _____ of a magnet.

• (A) Centre
• (B) Poles
• (C) Middle
• (D) Base

Question 7. Like poles of two magnets _____ each other.

• (A) Attract
• (B) Repel
• (C) Join
• (D) Ignore

Question 8. Unlike poles of two magnets _____ each other.

• (A) Repel
• (B) Attract
• (C) Break
• (D) Rotate

Question 9. Which is the surest test of a magnet?

• (A) Attraction
• (B) Repulsion
• (C) Weight
• (D) Colour

Question 10. A freely suspended magnet always points in the _____ direction.

• (A) East-West
• (B) North-South
• (C) North-East
• (D) South-East

Question 11. The Earth behaves like a giant _____.

• (A) Planet
• (B) Magnet
• (C) Star
• (D) Satellite

Question 12. Which instrument is used to find directions?

• (A) Telescope
• (B) Compass
• (C) Microscope
• (D) Thermometer

Question 13. A compass contains a _____.

• (A) Glass rod
• (B) Magnetised needle
• (C) Iron rod
• (D) Plastic strip

Question 14. Which ancient Indian navigation device is mentioned in the chapter?

• (A) Sundial
• (B) Matsya Yantra
• (C) Astrolabe
• (D) Sextant

Question 15. Which of the following is a non-magnetic material?

• (A) Iron
• (B) Nickel
• (C) Wood
• (D) Cobalt

Question 16. Magnetic force can pass through _____.

• (A) Plastic
• (B) Glass
• (C) Cardboard
• (D) All of these

Question 17. Which object commonly uses magnets?

• (A) Refrigerator door
• (B) Notebook
• (C) Pencil
• (D) Eraser

Question 18. Which of the following should NOT be done with a magnet?

• (A) Store carefully
• (B) Heat it
• (C) Use keepers
• (D) Keep in pairs

Question 19. A broken magnet always forms _____.

• (A) One pole
• (B) Two new magnets
• (C) No poles
• (D) Only a North Pole

Question 20. Which pole points towards geographic north?

• (A) South Pole
• (B) North Pole
• (C) Centre
• (D) Middle

Question 21. Which of the following is NOT a shape of a magnet?

• (A) Bar
• (B) Ring
• (C) Horseshoe
• (D) Triangle

Question 22. Which material is commonly used to make keepers?

• (A) Copper
• (B) Soft Iron
• (C) Aluminium
• (D) Plastic

Question 23. The magnetic property of a needle can be produced by _____.

• (A) Heating
• (B) Rubbing with a magnet
• (C) Cooling
• (D) Painting

Question 24. Magnets should be kept away from _____.

• (A) Wooden blocks
• (B) Electronic devices
• (C) Paper
• (D) Cotton

Question 25. Which pair shows attraction?

• (A) N-N
• (B) S-S
• (C) N-S
• (D) None

Question 26. Which pair shows repulsion?

• (A) N-S
• (B) S-N
• (C) N-N
• (D) Both A and B

Question 27. Lodestone is a _____.

• (A) Natural magnet
• (B) Artificial magnet
• (C) Metal rod
• (D) Plastic object

Question 28. Magnets are used in _____.

• (A) Speakers
• (B) Electric motors
• (C) Toys
• (D) All of these

Question 29. Which property helps sailors find directions?

• (A) Floating
• (B) North-South alignment
• (C) Colour
• (D) Weight

Question 30. The strongest magnetic effect is observed near the _____.

• (A) Centre
• (B) Poles
• (C) Middle
• (D) Bottom

Question 31. Which of the following is NOT attracted by a magnet?

• (A) Iron nail
• (B) Steel clip
• (C) Plastic spoon
• (D) Nickel coin

Question 32. What happens when unlike poles come close?

• (A) Repel
• (B) Attract
• (C) Break
• (D) Melt

Question 33. Which property makes magnets useful in cranes?

• (A) Colour
• (B) Attraction
• (C) Weight
• (D) Shape

Question 34. A compass needle is free to _____.

• (A) Float
• (B) Rotate
• (C) Break
• (D) Bend

Question 35. Which of the following weakens a magnet?

• (A) Proper storage
• (B) Heating
• (C) Using keepers
• (D) Careful handling

Question 36. Which scientist's work led to a better understanding of Earth's magnetism?

• (A) William Gilbert
• (B) Isaac Newton
• (C) Galileo
• (D) Einstein

Question 37. Which material is most suitable for testing magnetic attraction?

• (A) Iron nail
• (B) Wooden stick
• (C) Plastic ruler
• (D) Glass rod

Question 38. A compass works because of the Earth's _____.

• (A) Gravity
• (B) Rotation
• (C) Magnetic field
• (D) Atmosphere

Question 39. Which statement is correct?

• (A) Every magnet has one pole.
• (B) Every magnet has two poles.
• (C) Magnets attract all materials.
• (D) Magnets have no poles.

Question 40. Which statement about magnets is correct?

• (A) They should be hammered regularly.
• (B) They should be heated before use.
• (C) They should be stored carefully to retain magnetism.
• (D) They should always be broken into pieces.

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Answer Key

1. B
2. B
3. C
4. B
5. B
6. B
7. B
8. B
9. B
10. B
11. B
12. B
13. B
14. B
15. C
16. D
17. A
18. B
19. B
20. B
21. D
22. B
23. B
24. B
25. C
26. C
27. A
28. D
29. B
30. B
31. C
32. B
33. B
34. B
35. B
36. A
37. A
38. C
39. B
40. C