Maharashtra Board Class 6 Science Chapter 15 Fun with Magnets Solutions

Std 6 Science Chapter 15 Fun with Magnets Question Answer Maharashtra Board

Class 6 Science Chapter 15 Fun with Magnets Question Answer Maharashtra Board

1. How Will You Do This?

Question a. Determine whether a material is magnetic or non-magnetic.
Answer:
1. To determine whether the material is magnetic or non-magnetic, a magnet is moved over it.
2. If the material sticks to the magnet, it is called magnetic material.
3. If the material does not stick to the magnet, it is non-magnetic.
In simple words: You can test if a material is magnetic by seeing if a magnet attracts it. If it sticks, it's magnetic; if not, it's non-magnetic.

🎯 Exam Tip: Remember the basic test for magnetic materials: attraction to a magnet. This is a fundamental concept for understanding magnetism.

Question b. Explain that a magnet has a certain magnetic field.
Answer:
1. The space around a magnet in which the magnetic force is active is called the magnetic field.
2. Place a white paper on a drawing board and place a bar magnet in the middle of the paper.
3. Spread the iron filings on the sheet and gently tap the sheet.
4. The iron filings arrange around the magnet in definite curved lines forming a symmetric pattern.
5. The lines are closer to each other near the poles and less crowded in the middle region around the magnet.
6. Beyond a particular region, the iron filings, will not get attracted.
7. The region where iron filings are attracted is the magnetic field of the magnets.
In simple words: A magnetic field is the area around a magnet where its force can be felt. You can visualize it using iron filings, which show curved lines concentrated at the magnet's ends (poles).

🎯 Exam Tip: Understanding the magnetic field is crucial. Focus on the concept of force acting in space and how iron filings reveal the field lines, especially their density near the poles.

ℹ️ चित्र व्याख्या (Diagram Explanation): यह चित्र एक बार चुंबक के चारों ओर चुंबकीय क्षेत्र रेखाओं को दर्शाता है। ये रेखाएँ चुंबक के उत्तरी ध्रुव से निकलकर दक्षिणी ध्रुव में प्रवेश करती हुई दिखाई गई हैं, जो चुंबकीय बल की दिशा और पैटर्न को प्रस्तुत करती हैं। रेखाएँ ध्रुवों पर अधिक घनी होती हैं, जो उस क्षेत्र में मजबूत चुंबकीय बल को इंगित करती हैं।

Question c. Find the north pole of a magnet.
Answer:
1. Take a bar magnet. Tie a thread to the centre of a bar magnet and hang it from a stand.
2. Note the direction in which the magnet settles and turn it around again.
3. Allow it to settle and note the direction.
4. The end of the magnet that points to the north is called the north pole, while the end that points to the south is called the south pole.
5. The north pole is indicated by 'N' and the south pole by 'S'.
In simple words: To find the north pole, suspend a bar magnet freely; the end that points towards the Earth's geographic north is the magnet's north pole.

🎯 Exam Tip: The directional property of a freely suspended magnet (always aligning north-south) is a key characteristic and forms the basis for compasses. Be sure to label poles 'N' and 'S' correctly.

ℹ️ चित्र व्याख्या (Diagram Explanation): यह चित्र एक चुंबक को एक स्टैंड से धागे द्वारा स्वतंत्र रूप से लटका हुआ दिखाता है। यह व्यवस्था चुंबक के एक मूलभूत गुण को दर्शाती है कि जब इसे स्वतंत्र रूप से निलंबित किया जाता है, तो यह हमेशा उत्तर-दक्षिण दिशा में स्थिर होता है, जो इसके ध्रुवों को पहचानने में मदद करता है।

2. Which Magnet Will You Use?

Question a. Iron is to be separated from a trash.
Answer:
1. Sharp and heavy iron scrap material is attached to a big disc.
2. The disc is a magnet and all scrap is attracted to it.
3. It is not possible to create, store such a big size magnet. Therefore magnetism is induced in the disc with the help of electricity.
An electromagnet is used which is attached to a crane for loading and unloading, transporting scrap and loose iron material from a trash.
In simple words: To separate iron from trash, a powerful electromagnet attached to a crane is used because it can be turned on and off to pick up and release large amounts of magnetic scrap.

🎯 Exam Tip: Electromagnets are ideal for industrial applications like separating scrap metal due to their adjustable strength and temporary magnetism. Focus on their practical utility.

Question b. You are lost in a forest.
Answer:
1. If we are lost in a forest, we should take help of a mariner's compass which will help us to find the directions while travelling through unknown regions.
2. If mariner's compass is not available, a bar magnet when suspended in the centre will rest in north-south direction.
In simple words: If lost in a forest, use a mariner's compass or suspend a bar magnet to find the north-south direction, which helps in navigation.

🎯 Exam Tip: The ability of a magnet (or a compass) to align with Earth's magnetic field is a crucial navigational tool. Remember both the mariner's compass and a simple suspended magnet.

Question c. A window shutter opens and shuts continuously in the wind.
Answer:
A bar magnet can be attached to the window pane so that the window will be closed tight during strong winds also.
In simple words: To keep a window shutter closed in the wind, a bar magnet can be attached to the pane to securely hold it shut.

🎯 Exam Tip: This illustrates a simple, everyday application of magnetic attraction. Magnets provide a strong, reliable hold without mechanical latches.

3. Fill In The Blanks With Appropriate Word.

Question a. If a bar magnet is hung by a thread tied at its centre, its north pole becomes steady in the direction of the ............ pole of the earth. (south, north, east, west)
Answer: North
In simple words: A freely hanging bar magnet's north pole will always point towards the Earth's geographic north.

🎯 Exam Tip: This question tests the fundamental directional property of magnets. Always remember that a magnet's north pole points to the Earth's north.

Question b. If a bar magnet is cut into equal pieces by cutting it at right angles to its axis at two pieces ............... bar magnets are formed, and a total of ............... poles are formed. (6,3,2)
Answer: 3,6
In simple words: When a bar magnet is cut into three pieces, three smaller bar magnets are formed, each having a north and a south pole, making a total of six poles.

🎯 Exam Tip: Emphasize that poles always exist in pairs; even when cut, each piece becomes a complete magnet with two poles. The number of new magnets corresponds to the number of pieces.

Question c. There is a repulsion between the ............ poles of a magnet and attraction between its ............. poles. (opposite, like.)
Answer: like, opposite
In simple words: Like poles of a magnet repel each other, while opposite poles attract each other.

🎯 Exam Tip: This is a core law of magnetism. Remember: "Like repels, opposite attracts."

Question d. When magnetic material is taken close to a magnet, the material acquires ............ (permanent magnetism, induced magnetism, temporary, magnet keeper)
Answer: induced magnetism
In simple words: When a magnetic material is brought near a magnet, it temporarily becomes a magnet itself through induced magnetism.

🎯 Exam Tip: Induced magnetism is a key concept showing how a magnetic field can temporarily magnetize other materials without direct contact. It's often temporary.

Question e. If a magnet attracts a piece of metal, that piece must be made of ..............(any other metal but iron, magnetic material or iron, non-magnetic material, electromagnets)
Answer: magnetic material or iron
In simple words: If a magnet attracts a metal, that metal must be a magnetic material like iron, nickel, or cobalt, as only these are strongly affected by magnets.

🎯 Exam Tip: Always remember that magnets only attract specific "magnetic materials," primarily iron, nickel, and cobalt, or alloys containing them.

Question f. A magnet remains steady in a ............ direction. (east-west, north-south,)
Answer: north-south
In simple words: A freely suspended magnet will always come to rest aligning itself in the north-south direction due to the Earth's magnetic field.

🎯 Exam Tip: This property is the basis for compasses. It highlights the interaction of a magnet with the Earth's natural magnetic field.

4. Write The Answers In Your Words.

Question a. How is an electromagnet made?
Answer:
1. To make an electromagnet we need the following apparatus; An iron nail of 10 cm length, 1 metre long insulated copper wire, a battery cell, pins.
2. Wind the copper wire around the nail as shown in the figure. Connect the free ends of the wire to the two terminals of a cell through a plug key.
3. Close the key to complete the circuit.
4. Bring small pins near the tip of the nail and observe.
5. When the circuit is completed, the iron pins are attracted by the nail and hence, they stick to the nail.
6. When the circuit is broken, the pins fall off.
7. A magnet is prepared by passing an electric current through an insulated wire wound around the iron nail. This is an electromagnet.
8. When the current is allowed to pass, the nail becomes a magnet and attracts pin / pins stick to it.
9. When the current is put off the nail does not behave as a magnet and therefore, pins fall off.
10. The magnetism is temporary in the case of an electromagnet.
In simple words: An electromagnet is made by winding insulated copper wire around an iron core (like a nail) and passing an electric current through the wire. The iron core becomes magnetized when current flows and loses magnetism when the current is stopped.

🎯 Exam Tip: Focus on the three key components of an electromagnet: a current-carrying wire, an iron core, and a power source. Emphasize that its magnetism is temporary and controllable.

ℹ️ चित्र व्याख्या (Diagram Explanation): यह चित्र एक साधारण इलेक्ट्रोमैग्नेट (विद्युत चुंबक) के निर्माण को दर्शाता है। एक बैटरी सेल से विद्युत धारा एक लोहे की कील पर लिपटे हुए तांबे के तार से गुजरती है, जिससे कील अस्थायी रूप से चुंबकित हो जाती है और लोहे की पिंस को आकर्षित करती है। यह विद्युत और चुंबकत्व के बीच संबंध को प्रदर्शित करता है।

Question b. Write the properties of a magnet.
Answer:
Magnet possess following properties/ characteristics.
1. Magnet always settles in the north-south direction.
2. The magnetic force is concentrated at the two ends or poles of a magnet.
3. If a magnet is divided into two parts, two independent magnets are formed. It means that the two poles of a magnet cannot be separated from each other.
4. A magnetic material acquires magnetism when placed near a magnet. This magnetism is called induced magnetism.
5. There is repulsion between like poles of a magnet, while there is attraction between the opposite poles.
In simple words: Magnets always point north-south, have strongest force at their poles, cannot have isolated single poles, can induce magnetism in nearby materials, and show attraction between opposite poles and repulsion between like poles.

🎯 Exam Tip: Memorize these five fundamental properties, as they cover the essential behavior of all magnets. Pay special attention to the directional property and the law of magnetic poles.

Question c. What are the practical uses of a magnet?
Answer:
1. Magnets are materials to which objects made from iron, nickel, cobalt are attracted. But man explored magnets and its properties and made his life comfortable.
2. Permanent Magnets: are used in caps of pin holders, doors of fridges, doors of cupboards etc.
3. Temporary magnets: Electromagnets are used in electric bells, circuit of various machines, ATM card swipe machines, MRI- Magnetic Resonance Image, loudspeakers, electric cranes, microphones, Mariner's compasses, etc.
In simple words: Magnets are used in many daily items like fridge doors and pin holders, and electromagnets power complex devices such as electric bells, MRI machines, and cranes for lifting heavy objects.

🎯 Exam Tip: Differentiate between permanent and temporary magnet uses. Provide examples from both household items and industrial/medical applications to show a broad understanding.

Activity

Question 1. Collect information regarding how the various magnets used in our day-to-day tasks are produced.
Answer:
In simple words: Magnets are typically produced by magnetizing materials like iron or steel using strong magnetic fields, either from other magnets or electric currents, or by creating alloys that retain magnetism.

🎯 Exam Tip: For activity-based questions, describe a general method of production, highlighting the concept of magnetization of ferromagnetic materials.

Question 2. Collect information about the magnetism of the earth.
Answer:
In simple words: Earth acts like a giant magnet due to electric currents in its molten outer core, generating a magnetic field that extends into space and protects us from solar radiation.

🎯 Exam Tip: When discussing Earth's magnetism, mention its origin (molten core) and its significant role in protecting the planet.

Class 6 Science Chapter 15 Fun With Magnets Important Questions And Answers

Fill In The Blanks.

Question 1. Iron objects ............ to a magnet.
Answer: stick
In simple words: Iron objects are attracted to a magnet and will stick to it.

🎯 Exam Tip: This is a straightforward recall of basic magnetic attraction. Ensure the term "stick" or "attracted" is used.

Question 2. A magnet is used in ............ and ............ .
Answer: gadgets and machines
In simple words: Magnets are widely used in many everyday gadgets and various types of machines due to their unique properties.

🎯 Exam Tip: Think broadly about the applications of magnets in technology, from simple devices to complex machinery.

Question 3. The materials that stick to a magnet are called ......... materials.
Answer: magnetic
In simple words: Materials that are attracted to and stick to a magnet are called magnetic materials.

🎯 Exam Tip: Understand the definition of magnetic materials – those that interact with a magnet's field.

Question 4. Materials that do not stick to a magnet are called .............. materials.
Answer: non-magnetic
In simple words: Materials that are not attracted to a magnet are classified as non-magnetic materials.

🎯 Exam Tip: The distinction between magnetic and non-magnetic materials is fundamental; know examples of both categories.

Question 5. When a magnet attracts an object, that object is .............. due to the magnetic force.
Answer: displaced
In simple words: When a magnet pulls an object, the object moves from its original position, meaning it is displaced.

🎯 Exam Tip: This describes the observable effect of magnetic force: physical movement or displacement of magnetic objects.

Question 6. Magnetism is a form of ............ .
Answer: energy
In simple words: Magnetism is a fundamental force, and like other forces that can do work, it is considered a form of energy.

🎯 Exam Tip: Classifying magnetism as a form of energy is important, as it can cause motion and perform work.

Question 7. A magnet always settles in the .............. direction.
Answer: north-south
In simple words: A freely suspended magnet will always align itself along the Earth's north-south magnetic axis.

🎯 Exam Tip: This property is consistent and predictable, forming the basis for navigational tools.

Question 8. The north pole is indicated by' ........ and the south pole by '...............'.
Answer: 'N'-'S'
In simple words: The north pole of a magnet is typically labeled 'N', and the south pole is labeled 'S'.

🎯 Exam Tip: Standard labeling conventions for magnetic poles (N and S) are important for clear communication.

Question 9. The end of the magnet that points to the north is called the ............ .
Answer: Northpole
In simple words: The end of a freely suspended magnet that points towards the geographic north is defined as its North pole.

🎯 Exam Tip: This is a definitional question; understand how the North pole of a magnet is identified.

Question 10. The end of the magnet that points to the south is called the ............ .
Answer: South pole
In simple words: The end of a freely suspended magnet that points towards the geographic south is defined as its South pole.

🎯 Exam Tip: Similar to the North pole, know the definition and identification of the South pole.

Question 11. The magnetic force is concentrated at the two ends or ............ of a magnet.
Answer: poles
In simple words: The magnetic force of a magnet is strongest at its two ends, which are called the poles.

🎯 Exam Tip: The concentration of magnetic strength at the poles is a key characteristic, easily observed with iron filings.

Question 12. If a magnet is divided into two parts, two ............ magnets are formed.
Answer: independent
In simple words: When a magnet is cut, each resulting piece becomes a new, independent magnet with its own north and south poles.

🎯 Exam Tip: This illustrates the indivisible nature of magnetic poles – you cannot isolate a single pole by breaking a magnet.

Question 13. It means that the two poles of a magnet cannot be .............. from each other.
Answer: separated
In simple words: You can never separate the north and south poles of a magnet; they always exist as a pair.

🎯 Exam Tip: Reinforces the concept that magnetic monopoles do not exist; poles always come in pairs.

Question 14. A magnetic material acquires magnetism when placed near a ............ .
Answer: magnet
In simple words: A magnetic material temporarily becomes magnetized itself when it is brought close to an existing magnet.

🎯 Exam Tip: This describes induced magnetism, a temporary magnetization caused by proximity to another magnet.

Question 15. Iron filling stick to the iron bar when the .............. is near it.
Answer: magnet
In simple words: Iron filings cling to an iron bar only when a magnet is brought close to it, inducing magnetism in the bar.

🎯 Exam Tip: This is another example illustrating the principle of induced magnetism, where a non-magnet becomes temporarily magnetic.

Question 16. There is .............. between like poles of a magnet.
Answer: repulsion
In simple words: When two like poles (North-North or South-South) of magnets are brought together, they push each other away, which is called repulsion.

🎯 Exam Tip: This is a fundamental law of magnetic interaction: like poles repel, opposite poles attract.

Question 17. There is ............ between the opposite poles of a magnet.
Answer: attraction
In simple words: When two opposite poles (North-South) of magnets are brought together, they pull towards each other, which is called attraction.

🎯 Exam Tip: Understand both repulsion and attraction as core magnetic forces.

Question 18. Magnetic objects ............ magnetism.
Answer: induce
In simple words: Magnetic objects can temporarily cause or "induce" magnetism in other nearby magnetic materials.

🎯 Exam Tip: The term "induce" is specific to how magnetism is transferred or created temporarily in other materials.

Question 19. Material ............ is a mixture of aluminium, nickel and cobalt.
Answer: Alnico
In simple words: Alnico is a special alloy made from aluminium, nickel, and cobalt, known for making strong permanent magnets.

🎯 Exam Tip: Alnico is an important example of an alloy used to create powerful magnets; remember its constituent elements.

Question 20. ............ magnets are made from a mixture of nickel, cobalt and iron.
Answer: Permanent
In simple words: Permanent magnets are often created from mixtures of strong magnetic metals like nickel, cobalt, and iron.

🎯 Exam Tip: Permanent magnets retain their magnetism for a long time and are made from specific alloys.

Question 21. The bar of soft or pure iron which protects a magnet is called ............ .
Answer: magnet keeper
In simple words: A magnet keeper is a piece of soft iron used to bridge the poles of a magnet, protecting its magnetic strength when not in use.

🎯 Exam Tip: Magnet keepers are essential for preserving the strength of permanent magnets by preventing demagnetization.

Question 22. Magnetism gets ............... when a magnet is heated, thrown, knocked about or broken into pieces.
Answer: destroyed
In simple words: A magnet's magnetism can be lost or destroyed if it is heated, dropped forcefully, or broken into multiple pieces.

🎯 Exam Tip: Understand the factors that can lead to demagnetization, which are often related to disrupting the internal alignment of magnetic domains.

Question 23. Electromagnetic energy is used in our ............ life.
Answer: day-to-day
In simple words: Electromagnetic energy plays a significant role and is utilized in various aspects of our daily life, from household appliances to communication.

🎯 Exam Tip: Recognize the pervasive impact of electromagnetism in modern technology and daily living.

Question 24. The metals iron, cobalt, nickel are ............ materials.
Answer: magnetic
In simple words: Iron, cobalt, and nickel are metals that are strongly attracted to magnets and are therefore classified as magnetic materials.

🎯 Exam Tip: These three elements are the primary examples of ferromagnetic (magnetic) materials; remember them.

Question 25. ............ is a natural magnet.
Answer: Magnetite
In simple words: Magnetite is a naturally occurring mineral that possesses magnetic properties.

🎯 Exam Tip: Magnetite is the most common natural magnet and was historically known as lodestone.

Match The Columns.

Question a.

Column 'A'	Column 'B'
1. Iron, nickel, cobalt	(a) Electromagnet
2. Door bell magnet	(b) Permanent magnet
3. Nickel, cobalt, aluminium	(c) Magnetic metal
4. Cupboard magnet	(d) Mariner's compass
5. Lodestone	(e) Alnico

Answer:

Column 'A'	Column 'B'
1. Iron, nickel, cobalt	(c) Magnetic metal
2. Door bell magnet	(a) Electromagnet
3. Nickel, cobalt, aluminium	(e) Alnico
4. Cupboard magnet	(b) Permanent magnet
5. Lodestone	(d) Mariner's compass

In simple words: This matching exercise connects magnetic materials to their classifications, types of magnets to their uses, and specific alloys to their compositions.

🎯 Exam Tip: For matching questions, identify key terms and their most direct associations. Review definitions of magnetic materials, types of magnets, and their applications.

State Whether True Or False. If False, Correct The Statement.

Question 1. Material alnico is a mixture of aluminium, nickel and iron.
Answer: False: Material alnico is a mixture of aluminium, nickel and cobalt.
In simple words: Alnico is an alloy primarily composed of aluminum, nickel, and cobalt, not iron.

🎯 Exam Tip: Be precise with the composition of important alloys like Alnico. A common error is mixing up the elements.

Question 2. Magnetism of electromagnet is permanent.
Answer: False: Magnetism of electromagnet is temporary.
In simple words: An electromagnet's magnetism is temporary because it only works when an electric current flows through it.

🎯 Exam Tip: The key distinction between electromagnets and permanent magnets is the temporary nature of the former's magnetism, which can be controlled.

Question 3. The bar of soft or pure iron protects the magnet.
Answer: True
In simple words: A soft iron bar, known as a magnet keeper, helps to maintain the strength of a magnet by providing a closed loop for the magnetic field.

🎯 Exam Tip: Understand the role of magnet keepers in preventing demagnetization and why soft iron is used (easily magnetized and demagnetized).

Question 4. Like poles attract each other and unlike poles repel each other.
Answer: False: Like poles repel each other and unlike poles attract each other.
In simple words: The law of magnetism states that poles that are the same (like poles) push away from each other, while poles that are different (unlike poles) pull towards each other.

🎯 Exam Tip: This is a fundamental law. Ensure you correctly state "like repels, unlike attracts."

Question 5. The magnetic force is concentrated at the centre of the magnet.
Answer: False: The magnetic force is concentrated at the poles of the magnet
In simple words: The strongest magnetic force is found at the ends, or poles, of a magnet, not in its center.

🎯 Exam Tip: Remember that magnetic strength is highest at the poles, decreasing towards the center of the magnet.

Question 6. Magnetism is a kind of energy.
Answer: True
In simple words: Magnetism is a form of energy because it can exert forces and do work, such as moving magnetic objects.

🎯 Exam Tip: Recognize magnetism's status as a form of energy, similar to mechanical or electrical energy.

Question 7. Mariner's compass is used for finding directions while travelling.
Answer: True
In simple words: The mariner's compass is a crucial tool used by travelers, especially at sea, to determine direction based on Earth's magnetic field.

🎯 Exam Tip: The primary function of a mariner's compass is navigation; understand its purpose.

Question 8. Cobalt is a magnetic material.
Answer: True
In simple words: Cobalt is one of the ferromagnetic metals, meaning it is strongly attracted to magnets and can be magnetized itself.

🎯 Exam Tip: Remember cobalt, along with iron and nickel, as key magnetic materials.

Question 9. The north pole is indicated by 'S' and the south pole is indicated by 'N'.
Answer: False: The north pole is indicated by 'N' and the south pole is indicated by 'S'.
In simple words: Conventionally, the north pole of a magnet is denoted by 'N' and the south pole by 'S'.

🎯 Exam Tip: Pay attention to the correct labeling of magnetic poles to avoid confusion.

Question 10. Electromagnetism is used in many places in our day-to-day life.
Answer: True
In simple words: Electromagnetism is a fundamental principle widely applied in various technologies that we use daily, such as motors, speakers, and data storage.

🎯 Exam Tip: Reflect on the broad applications of electromagnetism, from simple devices to complex electronic systems.

Answer The Following Questions In One Sentence.

Question 1. What is a magnet?
Answer:
In simple words: A magnet is a material that produces an invisible field, causing it to attract or repel other magnetic materials and to align itself in a specific direction when freely suspended.

🎯 Exam Tip: A concise definition should cover both the attractive/repulsive force and the directional property of a magnet.

 

Question 1. What is a magnet?
Answer: The material to which objects made from iron, nickel, cobalt get attracted is called as magnet.
In simple words: A magnet is a material that attracts objects made of iron, nickel, or cobalt.

🎯 Exam Tip: Remember the three main magnetic materials: iron, nickel, and cobalt.

 

Question 2. What is magnetism?
Answer: The property of a material to which objects made from iron, nickel, cobalt get attracted is called as magnetism.
In simple words: Magnetism is the natural force by which a magnet attracts specific metal objects.

🎯 Exam Tip: Distinguish between a magnet (the object) and magnetism (the property).

 

Question 3. What are magnetic materials?
Answer: Materials that stick to a magnet are called magnetic materials, e.g. cobalt, nickel, iron.
In simple words: Magnetic materials are substances like iron, nickel, and cobalt that are attracted to a magnet.

🎯 Exam Tip: Provide examples like iron, nickel, and cobalt to illustrate magnetic materials.

 

Question 4. What are non-magnetic materials?
Answer: Materials that do not stick to a magnet are called non-magnetic material, e.g. plastic, rubber, glass etc.
In simple words: Non-magnetic materials are substances like plastic, rubber, and glass that are not attracted by a magnet.

🎯 Exam Tip: When defining, always include examples for clarity and better understanding.

 

Question 5. What are lodestones?
Answer: Lodestones are leading stones which are used for finding the directions while travelling through unknown regions.
In simple words: Lodestones are naturally occurring magnetic rocks used historically for navigation due to their ability to point north.

🎯 Exam Tip: Highlight the historical significance of lodestones in navigation.

 

Question 6. How is magnetism a kind of energy?
Answer: Work is done by magnetic force. Thus, magnetism is a kind of energy.
In simple words: Magnetism is a form of energy because magnetic forces can do work, like attracting or repelling objects.

🎯 Exam Tip: Connect the concept of "work done" by a force to energy to explain why magnetism is a form of energy.

 

Question 7. What is an electromagnet?
Answer: When magnetism is produced in the iron due to the electric current, it is called an electromagnet.
In simple words: An electromagnet is a temporary magnet created when an electric current flows through a wire wound around an iron core.

🎯 Exam Tip: Emphasize that electromagnets are "temporary" and rely on electric current.

 

Question 8. How are permanent magnets made?
Answer: Permanent magnets are made from a mixture of nickel, cobalt and iron.
In simple words: Permanent magnets are created by combining magnetic materials like nickel, cobalt, and iron, which retain their magnetism for a long time.

🎯 Exam Tip: Listing the constituent elements (nickel, cobalt, iron) is crucial for this answer.

 

Question 9. List the instruments where electromagnets are used.
Answer: Electromagnets are used in doorbells, cranes, loudspeakers, voltameters, TVs, antennas, radios etc.
In simple words: Electromagnets are widely used in devices such as doorbells, cranes, speakers, and various electronic appliances.

🎯 Exam Tip: Provide a diverse list of common applications to show the widespread use of electromagnets.

 

Question 10. How is magnetism destroyed?
Answer: When magnets are heated, thrown, knocked about or broken into pieces, magnetism gets destroyed.
In simple words: Magnetism can be destroyed by heating a magnet, dropping it forcefully, or breaking it into pieces.

🎯 Exam Tip: Focus on the common methods that can demagnetize a magnet: heat and physical shock.

 

Question 11. What is a magnet keeper?
Answer: A magnet keeper is a bar of soft or pure iron which protects a magnet. It is a piece of soft iron placed in the box in which a magnet is kept.
In simple words: A magnet keeper is a piece of soft iron used to store magnets, helping them retain their magnetic strength by providing a closed magnetic circuit.

🎯 Exam Tip: Explain the *purpose* of a magnet keeper, which is protection and preservation of magnetism.

 

Question 12. Magnets exist in variety of shapes.
Answer: Today, magnets are used in many machines, gadgets and devices. They are all man-made. Hence, they can have a variety of shapes depending upon their use.
In simple words: Modern magnets are man-made and designed in various shapes to suit specific applications in machines and gadgets.

🎯 Exam Tip: Relate the variety of shapes to the specific utility and design requirements of different applications.

Answer the following briefly.

 

Question 1. What are leading stones?
Answer:
1. It was known quite long ago to the people in China and Europe that a piece of magnetite, hung freely always settled in the north-south direction.
2. These rocks then came to be used for finding the directions while travelling through unknown regions.
3. That is why they are called leading stones or Lodestones.
In simple words: Leading stones, also known as lodestones, are naturally magnetic magnetite rocks that were historically used for navigation because they align themselves in a north-south direction when freely suspended.

🎯 Exam Tip: Mention both names (leading stones and lodestones) and their primary historical use for navigation.

 

Question 2. What has led to the invention of the Mariner's compass?
Answer: Leading stones have led to the invention of the mariner's compass.
In simple words: The observation that leading stones (lodestones) consistently pointed north-south inspired the invention of the mariner's compass for directional guidance.

🎯 Exam Tip: Focus on the direct cause-and-effect relationship between leading stones and the compass invention.

 

Question 3. List the different shapes of magnets.
Answer:
1. Magnets have a variety of shapes depending on their uses.
2. They are bar magnets, disc magnets, horseshoe magnets, ring shaped magnets, cylindrical magnets, and small button magnets.
In simple words: Magnets come in many shapes, including bar, disc, horseshoe, ring, cylindrical, and button, each designed for specific uses.

🎯 Exam Tip: Provide a diverse list of magnet shapes to show their versatility.

 

Question 4. What are permanent magnets?
Answer:
1. Magnets which do not lose their magnetism easily are called permanent magnets or Magnets which are made up of magnetic substances are permanent magnets.
2. e.g. Magnets fixed in a pin holder, magnets of a door of a cupboard are permanent magnets.
3. Permanent magnets are made from a mixture of
• Nickel, cobalt, iron
• Aluminium, nickel, cobalt - alnico
In simple words: Permanent magnets are materials that retain their magnetic properties for a long time, made from mixtures of elements like nickel, cobalt, and iron, and are commonly found in items like pin holders and cupboard doors.

🎯 Exam Tip: Key points are their long-lasting magnetism, the materials they are made from (e.g., Alnico), and common examples.

Give scientific reasons.

 

Question 1. Why is it important to place a magnet keeper in a box along with magnets?
Answer: Magnetism gets destroyed when a magnet is heated, thrown, knocked about or broken into pieces. A magnet keeper which is a bar of soft or pure iron protects a magnet.
In simple words: Magnet keepers are placed with magnets to prevent demagnetization caused by external factors like heat or physical impact, thus preserving their magnetic strength over time.

🎯 Exam Tip: Explain both the cause of magnetism destruction and how the keeper mitigates it.

 

Question 2. Cranes with magnets are used.
Answer: When a magnet attracts an object, that object is displaced due to the magnetic force. In factories, ports, garbage depots, large objects are lifted and shifted from place to place using cranes. Hence cranes are fitted with magnets.
In simple words: Cranes use powerful electromagnets to lift and move heavy iron objects efficiently in industrial settings, making it easy to transport large quantities of scrap or other materials.

🎯 Exam Tip: Emphasize the "lifting and shifting" function of magnetic cranes for heavy objects in industrial applications.

Can you tell?

 

Question 1. Pins in a pin holder do not fall? While we are shutting the door of a fridge, we find that it closes automatically from certain distance and does not open unless pulled again.
Answer: Magnet is fitted in the cap of a pin holder and in the door of a fridge. Iron objects stick to the magnet.
In simple words: Pins in a holder stay because of a magnet in the cap, and fridge doors close automatically due to magnets in the seal, both using magnetic attraction to hold iron objects or surfaces.

🎯 Exam Tip: Identify the presence of magnets in both scenarios and their function of attracting iron-containing items.

 

Question 2. Take a magnet from the laboratory and bring it near various objects in your use. Which of them stick to the magnet? What material is each of them made of? Observe these things carefully. Classify the objects into two groups: those which stick to the magnet, those which do not.
Comb, table, cupboard - iron, spoon, scissors, pen, pencil, eraser, books, mobile, laptops, glass bangles, hair pin, cupboard handle, chair, steel lunch box, magnetic stickers, toys, gold ring.
Answer:

Stick to the magnet	Doesn't stick to the magnet
Iron cupboard, spoon, scissors, hairpin, steel lunch box, magnetic stickers	Comb, table, pen, pencil, eraser, books, glass bangles, chair, mobile, laptops, cupboard handle, toys, gold ring

In simple words: When tested, objects made of magnetic materials like iron (cupboard, spoon, scissors) will stick to the magnet, while non-magnetic items such as plastic, wood, or glass (comb, table, glass bangles) will not.

🎯 Exam Tip: This question tests practical classification based on magnetic properties. Clearly list items into magnetic and non-magnetic categories.

 

Question 3. Take a mixture of sand, pieces of paper, sawdust, iron filings and pins in a saucer and pass a magnet around the mixture. What do you see?
Answer: When magnet is moved over a mixture of sand, pieces of paper, sawdust, iron filings and pins, pins and iron filings will cling to the magnet. Sand, sawdust and pieces of paper will remain behind.
In simple words: A magnet will attract and separate the iron filings and pins from the mixture, leaving behind the non-magnetic materials like sand, paper, and sawdust.

🎯 Exam Tip: This demonstrates how magnets are used for separation of magnetic materials from non-magnetic ones.

 

Question 4. How is a Mariner's Compass used?
Answer:
1. A Mariner's Compass is a magnetic needle used in navigation to show direction by deflections.
2. It is a direction-finding instrument used in navigation.
3. It is placed on the maps, grounds, decks as it will point to the magnetic north pole.
4. It has two or more magnets permanently attached to a compass card which moves freely on a pivot.
5. The needle fixed on the compass bowl indicates the ship's heading position.
In simple words: A mariner's compass, equipped with magnetic needles, is used for navigation by aligning with the Earth's magnetic north pole, helping determine direction on maps or during travel.

🎯 Exam Tip: Detail its navigational purpose, how it works (pointing to magnetic north), and its typical placement.

 

Question 5. Find out where the magnet given are used?
Answer:

Magnets	Uses
Horseshoe magnet	used in electric bell
Circular magnet	used in loudspeaker.
Magnetic needle	used in Mariner's Compass.
Disc magnets	used in toys
Bar magnets	used in cupboard doors
Button magnet	supporting side rails or blockouts
Square magnet	Industries
Arc magnet	Electric motors and generators.
Cylindrical magnet	used in medicine, used in treatment of scoliosis patients.

In simple words: Different magnet shapes have specific uses: horseshoe magnets in electric bells, circular magnets in loudspeakers, magnetic needles in compasses, disc magnets in toys, bar magnets in cupboard doors, button magnets for support, square magnets in industries, arc magnets in motors, and cylindrical magnets in medical treatments.

🎯 Exam Tip: Memorize the common uses associated with specific magnet shapes for practical applications.

 

Question 6. Identify the different types of magnets as shown in the picture below.
ℹ️ चित्र व्याख्या (Diagram Explanation): इस चित्र में चार अलग-अलग चुम्बकों को दिखाया गया है। (a) एक गोलाकार चुम्बक है। (b) एक बेलनाकार चुम्बक है। (c) एक घोड़े की नाल के आकार का चुम्बक है। (d) एक आयताकार या बार चुम्बक है।
Answer:
a. Circular magnet
b. Cylindrical magnet
c. Horseshoe magnet
d. Bar magnet
In simple words: The diagram illustrates various types of magnets, including a circular magnet, a cylindrical magnet, a horseshoe magnet, and a bar magnet, each having distinct shapes for different applications.

🎯 Exam Tip: Be able to visually identify and name the common shapes of magnets.