Samacheer Kalvi Class 6 Science Solutions Term 3 Chapter 1 Magnetism

Samacheer Kalvi 6th Science Magnetism Text Book Back Questions And Answers

I. Choose the Correct Answer:

 

Question 1. An object that is attracted by a magnet.
(a) wooden piece
(b) plain pins
(c) eraser
(d) a piece of paper
Answer: (b) Plain pins
In simple words: Plain pins are made of metal, so a magnet can pull them. Things like wood, erasers, and paper are not attracted to magnets.

🎯 Exam Tip: Remember that magnets attract only magnetic materials like iron, nickel, and cobalt. Non-magnetic materials are not affected.

 

Question 2. People who made mariner's compass for the first time.
(a) Indians
(b) Europeans
(c) Chinese
(d) Egyptians
Answer: (c) Chinese
In simple words: The Chinese were the first people to create the mariner's compass, which helped sailors find their way on the sea.

🎯 Exam Tip: Knowing the historical origins of important inventions like the compass can help you understand its significance and use.

 

Question 3. A freely suspended magnet always comes to rest in the direction
(a) North-east
(b) South-west
(c) East-west
(d) North-south
Answer: (d) North-South
In simple words: When you hang a magnet freely, it will always turn to point towards the Earth's North and South poles. This is how a compass works.

🎯 Exam Tip: Always remember that a freely suspended magnet aligns itself with the Earth's magnetic field, pointing approximately North-South.

 

Question 4. Magnets lose their properties when they are
(a) used
(b) stored
(c) hit with a hammer
(d) cleaned
Answer: (c) hit with a hammer
In simple words: Hitting a magnet, heating it, or dropping it from a height can make it lose its ability to attract other metals.

🎯 Exam Tip: To keep magnets strong, avoid hitting them, heating them, or storing them improperly. They are delicate in that sense.

 

Question 5. Mariner's compass is used to find the
(a) speed
(b) displacement
(c) direction
(d) motion.
Answer: (c) direction
In simple words: The mariner's compass is a tool that helps people, especially sailors, find their way by showing them which direction is north, south, east, or west.

🎯 Exam Tip: Understand the primary purpose of a mariner's compass, which is crucial for navigation by indicating direction.

II. Fill in the Blanks

 

Question 1. Artificial magnets are made in different shapes such as .................. and ..................
Answer: Oval shape, Disc shape, cylindrical shape
In simple words: Magnets made by people can be found in many shapes, like oval, round (disc), or tube-like (cylindrical).

🎯 Exam Tip: When asked about shapes of artificial magnets, recall common forms like bar magnets, horseshoe magnets, and disc magnets.

 

Question 2. The Materials which are attracted towards the magnet are called ..................
Answer: magnetic materials
In simple words: Things that a magnet can pull are called magnetic materials, such as iron.

🎯 Exam Tip: Clearly distinguish between magnetic materials (attracted by magnets) and non-magnetic materials (not attracted by magnets).

 

Question 3. Paper is not a .................. material.
Answer: magnetic
In simple words: Paper is not a material that a magnet can attract. It is called non-magnetic.

🎯 Exam Tip: Provide clear examples of non-magnetic materials like paper, plastic, and wood to illustrate the concept.

 

Question 4. In olden days, sailors used to find direction by suspending a piece of ..................
Answer: lodestone
In simple words: Long ago, sailors used a natural magnet stone, called a lodestone, to figure out directions while sailing.

🎯 Exam Tip: Remember lodestone as a natural magnet that played a key role in early navigation before artificial magnets were common.

 

Question 5. A magnet always has .......... poles.
Answer: Two
In simple words: Every magnet, no matter how small, will always have a north pole and a south pole. These two poles work together.

🎯 Exam Tip: Emphasize that poles always exist in pairs, and you cannot have a magnet with only one pole.

III. True or False. If False, Give the Correct Answer.

 

Question 1. A cylindrical magnet has only one pole.
Answer: False – A cylindrical magnet has two poles.
In simple words: This statement is not true. Even a cylinder-shaped magnet, like all magnets, has two ends: a north pole and a south pole.

🎯 Exam Tip: All magnets, regardless of their shape, always have two poles: a North pole and a South pole. This is a fundamental property of magnetism.

 

Question 2. Similar poles of a magnet repel each other.
Answer: True
In simple words: This is correct. If you bring two north poles together, or two south poles together, they will push each other away.

🎯 Exam Tip: Remember the basic rule of magnets: like poles repel (push away), and unlike poles attract (pull together).

 

Question 3. Maximum iron filings stick in the middle of a bar magnet when it is brought near them.
Answer: False – Maximum iron fillings stick in the poles of a bar magnet when it is brought near them.
In simple words: This is wrong. The strongest parts of a magnet are its ends, called poles. So, most iron filings will stick to the poles, not the middle.

🎯 Exam Tip: The magnetic strength of a bar magnet is greatest at its poles (ends) and weakest in the middle.

 

Question 4. A compass can be used to find East-West direction at any place.
Answer: False – A compass can be used to find north-south direction at any place.
In simple words: This is incorrect. A compass always points to the North-South direction, not East-West. Once you know North, you can find East and West.

🎯 Exam Tip: The primary function of a compass is to indicate the North-South direction, which then helps in determining other directions.

 

Question 5. Rubber is a magnetic material.
Answer: False – Rubber is a non-magnetic material.
In simple words: This statement is false. Rubber is not attracted by magnets, so it is known as a non-magnetic material.

🎯 Exam Tip: Be able to give examples of both magnetic materials (like iron) and non-magnetic materials (like rubber, wood, plastic).

IV. Match the Following

 

Question 1. Match the following.

Answer:
1. - d (Compass - Magnetic needle)
2. - c (Attraction - Opposite poles)
3. - b (Repulsion - Like poles)
4. - a (Magnetic poles - Maximum magnetic strength)
In simple words: A compass uses a magnetic needle. Opposite ends of magnets pull each other. Similar ends of magnets push each other away. The strongest part of a magnet is at its poles.

🎯 Exam Tip: Understand the key terms related to magnetism and their definitions to correctly match them. Focus on the core principles of attraction and repulsion.

V. Circle the Odd Ones And Give Reasons

 

Question 1. Iron, nail, pins, rubber tube, needle
Answer: Rubber tube. Rubber tube is a non-magnetic substance.
In simple words: All the other things like iron, nails, pins, and needles are made of metals that magnets can attract. Rubber tube is the odd one out because it is not attracted by magnets.

🎯 Exam Tip: To identify the odd one out, you need to classify materials as magnetic or non-magnetic based on whether they are attracted to a magnet.

 

Question 2. Lift, escalator, electromagnetic train, electric bulb
Answer: Electric bulb. Electromagnet is not used in an electric bulb.
In simple words: Lifts, escalators, and electromagnetic trains all use electromagnets to work. An electric bulb, however, works differently and does not use an electromagnet.

🎯 Exam Tip: Think about which items use magnetic principles (especially electromagnets) in their operation to find the one that doesn't fit.

 

Question 3. Attraction, repulsion, pointing direction, illumination
Answer: Illumination. Illumination is not a magnetic property.
In simple words: Attraction, repulsion, and pointing in a certain direction are all things that magnets do. Illumination means giving out light, which has nothing to do with magnets.

🎯 Exam Tip: Focus on properties specifically associated with magnets and their interactions to distinguish them from general physical phenomena.

 

Question 1. The following diagrams show two magnets near one another. Use the words, 'Attract, Repel, Turn around' to describe what happens in each case:
Answer:
(a) Attract. Opposite poles (S-N) pull each other together.
(b) Repel. Like poles (S-S) push each other away.
(c) Attract. Opposite poles (N-S) pull each other together.
(d) Turn around. (The magnet will rotate to align itself with the other magnet's field)
(e) Repel. Like poles (N-N) push each other away.
(f) Turn around. (The magnet will rotate to align itself with the other magnet's field)
In simple words: When opposite ends of magnets are close, they pull together (attract). When similar ends are close, they push apart (repel). If a magnet is freely placed near another, it might also just spin until its opposite pole faces the other magnet.

🎯 Exam Tip: Remember that opposite poles attract, and like poles repel. A magnet can also "turn around" if it is free to move, to bring its opposite pole closer.

VII. Write Down The Names Of Substances.

 

Question 1. Write down the names of substances (magnetic and non-magnetic).
Answer:
Substances attracted by magnets (Magnetic substances): Safety pins, Iron rod, Nickle, Cobolt, Plain pins, Hair pins, Needle.
Substances not attracted by magnets (Non-magnetic substances): Door lock, Plastic Toy car, Ebonite, Glass, Wooden piece, Eraser, Rubber, Chalk piece, Plastic box.
In simple words: Things like iron, nickel, and cobalt are magnetic because magnets pull them. Things like wood, plastic, glass, and rubber are non-magnetic because magnets do not pull them.

🎯 Exam Tip: Always be prepared to list common examples for both magnetic and non-magnetic materials, as this demonstrates understanding of the concept.

VIII. Give Short Answer

 

Question 1. Explain the attraction and repulsion between magnetic poles.
Answer:
1. Like poles (North-North, South-South) push each other away.
2. Unlike poles (North-South, South-North) pull each other together.
In simple words: When the same ends of two magnets are brought close, they push away (repel). When different ends are brought close, they pull together (attract).

🎯 Exam Tip: This is a fundamental concept of magnetism; clearly state the rule for both like and unlike poles to score full marks.

 

Question 2. A student who checked some magnets in the school laboratory found out that their magnetic force is worn out. Give three reasons for that?
Answer: Magnets lose their properties if they are heated or dropped from a height or hit with a hammer.
In simple words: Magnets can become weak if they are made hot, fall from a distance, or are hit hard with something like a hammer.

🎯 Exam Tip: Remember the main factors that can demagnetize a magnet: heating, hammering, and dropping. Proper storage is also essential.

IX. Answer in Detail

 

Question 1. You are provided with an iron needle. How will you magnetize it?
Answer:
1. First, place the iron needle on a flat surface like a table.
2. Take a bar magnet and put one of its ends close to one edge of the iron needle.
3. Rub the magnet from one end of the needle to the other. Do this without changing the direction of the magnet's pole. You should always rub in the same direction.
4. Do this rubbing process about 30 to 40 times. The needle will then become magnetized.
5. If the needle still does not attract small pins or iron filings, continue the same rubbing process for a bit longer until it does. This process is called magnetic induction.
In simple words: To make an iron needle into a magnet, rub it many times with one end of a strong magnet, always in the same direction. After many rubs, the needle will gain magnetic power.

🎯 Exam Tip: Clearly list the steps for making a temporary magnet by the single touch method, ensuring you mention consistent rubbing direction and number of repetitions.

 

Question 2. How does electromagnetic train work?
Answer:
1. Electromagnets are used in electromagnetic trains, often called Maglev trains.
2. These electromagnets become magnetized when electricity flows through them. If the direction of the electric current is changed, the poles of the magnets also change.
3. Magnets are placed at the bottom of the train and also along the rail tracks.
4. The train is lifted a small height, often up to 10 cm, from the track. This happens because the like poles of the magnets on the train and track push each other away (repel). This makes the train float.
5. By using both attraction (pulling) and repulsion (pushing) between the magnets at the same time, the train is made to move forward.
6. All these magnets are carefully controlled by electricity, allowing precise movement.
7. Because the train floats and does not touch the track, there is no friction. This allows the train to reach very high speeds, like 300 km/h, smoothly.
In simple words: Electromagnetic trains float above the tracks using electromagnets. Electricity makes these magnets push the train up and forward. Since there is no rubbing (friction), these trains can go very fast.

🎯 Exam Tip: Focus on the two main principles of Maglev trains: magnetic levitation (lifting) due to repulsion and propulsion (moving forward) using controlled attraction and repulsion. Mentioning the role of electricity and lack of friction is crucial.

X. Questions Based On Higher Order Thinking Skills

 

Question 1. You are provided with iron filings and a bar magnet without labelling the poles of the magnet. Using this ......... a. How will you identify the poles of the magnet?
Answer:
1. When we place the bar magnet into iron filings, a large number of iron filings will stick strongly to the two ends of the bar magnet. These ends are the poles of the magnet.
2. The poles will attract more iron filings because the magnetic strength is highest at the poles.
In simple words: To find the poles of a magnet, dip it into iron filings. The filings will stick mostly to the ends, showing where the poles are because those are the strongest parts.

🎯 Exam Tip: A practical way to locate the poles of a magnet is by observing where iron filings concentrate most intensely.

 

Question 1. b. Which part of the bar magnet attracts more iron filings? Why?
Answer: The poles of the magnet attract more iron filings because the poles have more concentrated magnetic power.
In simple words: The ends of a magnet, called its poles, pull in more iron filings. This is because all the magnetic power is focused at those two spots.

🎯 Exam Tip: Always remember that magnetic force is strongest at the poles and weakest in the middle of a bar magnet.

 

Question 2. Two bar magnets are given in figure A and B. By the property of attraction, identify the North pole and the South pole in the bar magnet (B) Fig-A S N Fig-B ? ?
Answer: Opposite poles attract each other. The second pole of magnet A is N (north pole). So, for magnet B to be attracted, its first pole must be S (south pole), and the second pole must be N (north pole). Therefore, magnet B has S-N poles.
In simple words: Since magnet A has North and South poles, and if magnet B is attracted to magnet A, then magnet B's poles must be opposite to A's. If magnet A ends with North, then magnet B must start with South. So, magnet B's poles are South and North.

🎯 Exam Tip: Use the fundamental rule that unlike poles attract to deduce the unknown poles of a magnet when it interacts with a known magnet.

Samacheer Kalvi 6th Science Magnetism Additional Important Questions And Answers

I. Choose the Right Answer:

 

Question 1. Which is not attracted by a magnet?
(a) Iron
(b) Cobalt
(c) Nickel
(d) Rubber
Answer: (d) Rubber
In simple words: Magnets can pull iron, cobalt, and nickel, but they cannot pull rubber. So, rubber is the one that is not attracted.

🎯 Exam Tip: Keep a mental list of common magnetic materials (iron, nickel, cobalt) and non-magnetic materials (wood, plastic, rubber) to quickly answer such questions.

 

Question 2. Among the following which one is a magnetic substance?
(a) Nickel
(b) Sodium
(c) Oxygen
(d) Potassium
Answer: (a) Nickel
In simple words: Out of the choices given, only nickel is a material that a magnet can attract. The others are not magnetic.

🎯 Exam Tip: Remember the three main ferromagnetic elements: Iron, Nickel, and Cobalt. These are the most common magnetic substances.

 

Question 3. Who invented leading stone?
(a) Indians
(b) Europeans
(c) Chinese
(d) Americans
Answer: (c) Chinese
In simple words: The Chinese were the first people to discover and use lodestone, a natural magnet, for navigation.

🎯 Exam Tip: Associate the invention and early use of lodestone (or natural magnets for direction) with ancient China.

 

Question 4. Magnets lose their properties if they are
(a) dipped in water
(b) dipped in oil
(c) heated
(d) in freezer
Answer: (c) heated
In simple words: If you make a magnet very hot, it will lose its ability to attract things. Water, oil, or cold temperatures generally do not make it lose its power.

🎯 Exam Tip: Heating a magnet above its Curie temperature causes it to lose its magnetic properties permanently.

 

Question 5. The maximum speed of electromagnetic train is
(a) 380 km/hr
(b) 600 km/h
(c) 480 km/h
(d) 690 km/h
Answer: (b) 600 km/h
In simple words: Electromagnetic trains can travel incredibly fast, reaching speeds of up to 600 kilometers per hour because they float and have no friction.

🎯 Exam Tip: Remember the approximate high speed of electromagnetic (Maglev) trains as an example of advanced magnetic technology.

II. Fill in the Blanks:

 

Question 1. Magnets are used to find directions. So they are called as ..................
Answer: leading stem
In simple words: Magnets help us find which way to go, so they are sometimes called "leading stems" because they guide us.

🎯 Exam Tip: The term "leading stem" refers to the guiding property of a magnet, especially in early compasses or lodestones.

 

Question 2. .................... is the ore with attracting property.
Answer: Magnetite
In simple words: Magnetite is a type of rock found in nature that can attract other metals, meaning it is a natural magnet.

🎯 Exam Tip: Magnetite is a natural magnetic ore and is historically significant as the first known magnetic material.

 

Question 3. Ever silver spoon is a .................. material.
Answer: non-magnetic
In simple words: A silver spoon is not attracted to a magnet, so it is a non-magnetic material.

🎯 Exam Tip: While some metals are magnetic, many are not. Silver, for instance, is a non-magnetic metal.

 

Question 4. .................... is used to seperate iron from wastages.
Answer: electromagnet
In simple words: Large, powerful electromagnets are used in factories to pick up and separate iron pieces from piles of garbage or other waste materials.

🎯 Exam Tip: Electromagnets are widely used in industries, especially for separating magnetic materials from non-magnetic ones in recycling or scrap yards.

 

Question 5. The attractive force of magnet is high near ..................
Answer: Poles
In simple words: A magnet pulls strongest at its ends, which are called the poles. The middle part is not as strong.

🎯 Exam Tip: This reinforces the concept that magnetic field lines are most dense and the force is strongest at the poles.

III. Match the Following.

 

Question 1. Match the Following.

Answer:
1. - v. (Natural magnet - Magnetite)
2. - iii. (Artificial magnet - Bar magnet)
3. - i. (Magnetic material - Plain pins)
4. - ii. (Electro magnet - Bullet trains)
5. - iv. (Poles - High attractive force)
In simple words: Magnetite is a natural magnet. A bar magnet is made by people. Plain pins are magnetic. Electromagnets help bullet trains move. The strongest pull of a magnet is at its poles.

🎯 Exam Tip: This matching exercise covers various aspects of magnetism, from types of magnets to their properties and applications. Review each pairing carefully.

IV. Very Short Answer Questions:

 

Question 1. What are artificial magnets?
Answer: Man-made magnets are called artificial magnets. For example, bar magnets and horseshoe magnets are artificial magnets.
In simple words: Artificial magnets are magnets that people create, unlike natural magnets found in the Earth. Bar magnets are a common type.

🎯 Exam Tip: Define artificial magnets by contrasting them with natural magnets and give a couple of common examples.

 

Question 2. What are the different types of artificial magnets?
Answer: Bar magnets, horseshoe magnets, ring magnets, and needle magnets are generally used as artificial magnets. Other shapes like oval, disc, and cylindrical magnets are also available.
In simple words: Magnets made by humans come in many shapes. Some common ones are bar-shaped, horseshoe-shaped, ring-shaped, or even like a needle.

🎯 Exam Tip: List a variety of shapes for artificial magnets, emphasizing their diverse applications.

 

Question 3. What are magnetic substances?
Answer: Substances which are attracted by magnets are called magnetic substances. Examples include iron, cobalt, and nickel.
In simple words: Magnetic substances are materials that a magnet can pull. Iron is a good example of a magnetic substance.

🎯 Exam Tip: Provide a clear definition and give examples of the three main ferromagnetic elements: iron, cobalt, and nickel.

 

Question 4. What are non-magnetic substances?
Answer: Substances which are not attracted by magnets are called non-magnetic substances. For example, paper and plastic.
In simple words: Non-magnetic substances are materials that a magnet cannot pull or affect, like wood, plastic, or paper.

🎯 Exam Tip: Define non-magnetic substances and offer common, easy-to-understand examples.

 

Question 5. What are the uses of magnets?
Answer:
1. We use many tools and devices with magnets in our daily lives.
2. Magnets are used in speakers, small electric motors, some door locks, bags, and certain toys.
3. They are also found in compasses, pencil boxes, phone covers, pin holders, and magnetic cranes.
In simple words: Magnets are everywhere! They are in your speakers, phone cases, toys, and even help big cranes lift metal. They are important in many tools we use daily.

🎯 Exam Tip: List a diverse range of applications, from common household items to industrial uses, to show a broad understanding of magnet utility.

V. Long Answer Questions:

 

Question 1. What are the storage methods of magnets?
Answer:
1. Improper storage can cause magnets to lose their magnetic properties over time.
2. To keep bar magnets safe and strong, they should be stored in pairs. Their opposite poles should be placed together on the same side.
3. A piece of wood should separate the two bar magnets. Additionally, two pieces of soft iron, called keepers, should be placed across their ends.
4. For a horseshoe magnet, a single piece of soft iron can be used as a magnetic keeper. It should be placed across its poles to complete the magnetic circuit and maintain strength.
In simple words: Magnets need to be stored carefully so they don't lose their power. Bar magnets should be kept in pairs with opposite poles facing each other, separated by wood, and with soft iron pieces at their ends. Horseshoe magnets need one soft iron piece across their ends.

🎯 Exam Tip: Detail the specific storage methods for both bar magnets (pairs with wooden spacer and keepers) and horseshoe magnets (single keeper), explaining why these methods are used (to prevent demagnetization).

 

Question 2. How to find directions with a magnet?
Answer:
1. Tie a piece of thread to the middle of a bar magnet. Then, hang it so it can swing freely.
2. Observe the direction in which the magnet comes to a stop. This direction will always be approximately North-South.
3. On a piece of cardboard placed under the magnet, draw a line along the direction the magnet is pointing. This line represents the North-South direction.
4. Gently turn the magnet and then let it come to a stop again. It will always return to the North-South alignment.
5. Repeat this process three or four times to confirm. The magnet consistently comes to rest in the North-South direction due to the Earth's magnetic field.
In simple words: To find directions with a magnet, hang it from a thread so it can spin freely. It will always stop pointing North and South. You can draw a line to mark this direction and use it to find East and West too.

🎯 Exam Tip: Clearly outline the steps for using a freely suspended magnet to determine geographical directions, highlighting the consistent North-South alignment.

VI. Questions Based On Higher-Order Thinking Skills:

 

Question 1. When iron needle is rubbed with bar magnet the needle get magnetized. But rubber piece is rubbed with magnet it will not get magnetized. Why?
Answer: Because rubber is a non-magnetic substance.
In simple words: An iron needle can become a magnet because iron is a magnetic material. Rubber cannot become a magnet because it is a non-magnetic material and does not respond to magnetic forces.

🎯 Exam Tip: Explain that only magnetic materials can be magnetized through induction or rubbing, while non-magnetic materials cannot.

 

Question 2. What will happen when we place magnets near cell phone, computer and DVD?
Answer:
1. Magnets will lose their property (demagnetize) if placed too close to strong magnetic fields.
2. Electronic objects like cell phones, computers, and DVDs can also get affected, leading to data loss or damage. Magnetic fields can interfere with their internal workings.
In simple words: Strong magnets can harm electronic devices like phones, computers, and DVDs. They can make the magnets inside these devices weak and can even erase stored information or damage parts.

🎯 Exam Tip: Advise caution when using magnets around electronics as strong magnetic fields can corrupt data and damage components due to electromagnetic interference.

VI. Questions Based On Higher-Order Thinking Skills

 

Question 1. When iron needle is rubbed with bar magnet the needle get magnetized. But rubber piece is rubbed with magnet it will not get magnetized. Why?
Answer: When an iron needle is rubbed with a bar magnet, the needle becomes magnetized because iron is a magnetic material. Magnetic materials can temporarily or permanently become magnets themselves. However, a rubber piece will not become magnetized when rubbed with a magnet because rubber is a non-magnetic substance. Non-magnetic materials do not interact with magnetic fields in the same way and cannot be induced to become magnets.
In simple words: An iron needle turns into a magnet because iron is magnetic. A rubber piece does not turn into a magnet because rubber is not a magnetic material and cannot hold magnetism.

🎯 Exam Tip: Differentiate between magnetic materials (like iron, nickel, cobalt) that can be magnetized and non-magnetic materials (like rubber, wood, plastic) that cannot.

 

Question 2. What will happen when we place magnets near cell phone, computer and DVD?
Answer: If magnets are placed near sensitive electronic devices like cell phones, computers, or DVDs, two main things can happen. Firstly, the magnets can cause the devices to lose their normal working properties or function incorrectly. Secondly, the strong magnetic field can damage the internal components or data stored on these objects. This is because electronics and data storage rely on precise magnetic or electrical signals, which can be disrupted by external magnets.
In simple words: Putting magnets near cell phones, computers, or DVDs can make them stop working properly. The magnets can also damage the electronic parts or erase data from these items.

🎯 Exam Tip: Always keep magnets a safe distance away from electronic gadgets and any devices that store digital data, such as hard drives or memory cards.