Text Book Back Questions and Answers - Chapter 1 Magnetism Term 3 6th Science Guide Samacheer Kalvi Solutions - SaraNextGen [2024-2025]

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On April 24, 2024, 11:35 AM

Textual Evaluation : Chapter 1 - Magnetism - Term 3 - 6th Science Guide Samacheer Kalvi Solutions
I. Choose the appropriate answer:
Question 1.
An object that is attracted by magnet.
(a) wooden piece
(b) plain pins
(c) eraser
(d) a piece of paper
Answer:
(b) plain pins

Question $2 .$
People who made mariner's compass for the first time.
a. Indians
b. Europeans
c. Chinese
d. Egyptians
Answer:
c. Chinese

Question $3 .$
A freely suspended magnet always comes to rest in the
(a) North - East
(b) South - West
(c) East - West
(d) North - South
Answer:
(d) 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

Question $5 .$
Mariner's compass is used to find the
(a) speed
(b) displacement
(c) direction
(d) motion
Answer:
(c) direction

II. Fill in the blanks:
1. Artificial magnets are made in different shapes such as ______, ______ and ______
2. The materials which are attracted towards the magnet are called______
3. Paper is not a ______material.
4. In olden days, sailors used to find direction by suspending a piece of______
5. A magnet always has ______poles.

Answers:
1. Bar-magnet, Horseshoe magnet, Ring magnet
2. magnetic substances
3. magnetic
4. lodestones
5. two

III. True or False. If False, give the correct statement:
Question $1 .$
A cylindrical magnet has only one pole.
Answer:
False. A cylindrical magnet has two poles.

Question $2 .$
Similar poles of a magnet repel each other.

Answer:
True.

Question $3 .$
Maximum iron filings stick in the middle of a bar magnet when it is brought near them.
Answer:
False. Maximum iron filings stick in the poles of a bar magnet when it is brought near them.

Question $4 .$
A compass can be used to find East-West direction at any place.
Answer:
True. A magnetic compass always points towards the North-South direction. If the North-South direction is known, then the East-West direction can also be determined. This direction is perpendicular to the North-South direction, ie., perpendicular to the compass needle in the same plane.

Question $5 .$
Rubber is a magnetic material.
Answer:
False. Rubber is anon-magnetic material.

IV. Match the following:
1. Compass - Maximum magnetic strength
2. Attraction - Like poles
3. Repulsion - Opposite poles
4. Magnetic poles - Magnetic needle

Answer:
1. Compass - Magnetic needle
2. Attraction-Opposite poles
3. Repulsion - Like poles
4. Magnetic poles - Maximum magnetic strength

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, others are magnetic substances.

Question $2 .$
Lift, escalator, electromagnetic train, electric bulb.
Answer:
Electric bulb.
Electric bulb does not have magnets others have electromagnets.

Question 3.
Attraction, repulsion, pointing direction, illumination.
Answer:
Illumination
Illumination is not a property of magnet, others are magnetic properties.

VI. 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. Unlike poles attract one another.
b. Like poles repel each other.
c. Unlike poles attract one another.
d. Perpendicular poles turn around and attract one another.
e. Like poles repel each other.
f. Perpendicular poles turn around and attract one another.

VII. Write down the names of substances:

Answer:

VIII. Give Short Answer:
Question $1 .$
Explain the attraction and repulsion between magnetic poles.
Answer:
1. Like poles $(\mathrm{N}-\mathrm{N}, \mathrm{S}-\mathrm{S})$ repel each other.
2. Unlike poles $(\mathrm{N}-\mathrm{S}, \mathrm{S}-\mathrm{N})$ attract each other.

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:
1. heated
2. dropped from a height
3. hit with a hammer

These are the reasons for that their magnetic force is worn out.

IX. Answer in detail:
Question $1 .$
You are provided with an iron needle. How will you magnetize it?
Answer:
1. Place the iron needle on the table.
2. Take a bar magnet and place one of its poles near one edge of the iron needle.
3. Rub from one end to another without changing the direction of the pole of the magnet.
4. Repeat the process for 30 to 40 times. The needle will be magnetized.
5. If it will not attract pin or iron fillings continue the same process for some more time.

Question $2 .$
How does an electromagnetic train work?
Answer:
1. Electromagnets are used in Electromagnetic train.
2. Electromagnets are magnetised only when current flows through them.
3. When the direction of current is changed, the poles of the electromagnets are also changed.
4. Like poles of the magnets which are attached at the bottom of the train and rail track repel each other.
5. So, the train is lifted from the track up to a height of $10 \mathrm{~cm}$.
6. We know that we can move any magnetic object with the force of attraction or repulsion properties of magnets.
7. This train also moves with the help of the magnets attached on the sides of track and the magnets fitted at the bottom sideway of the train.
8. By controlling the current, we can control the magnets and movement of the train.

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.
1. How will you identify the poles of the magnet?
2. Which part of the bar magnet attracts more iron filings? Why?
Answer:
1. When we place the bar magnet in iron fillings large amount of iron fillings stick on the two ends of the bar magnet. These ends are poles of the magnet.
2. Poles will attract more iron filings. Because poles have high magnetic strength.

Question $2 .$
Two bar magnets are given in the figure A and B. By the property of attraction, identify the North pole and the South pole in the bar magnet (B)

Answer:
The Fig -A has $\mathrm{S}$ and $\mathrm{N}$ poles.
In the Fig -B magnet, nearer to the North pole of Fig-A is South pole and the next pole is North pole.

Question $3 .$
Take a glass of water with a few pins inside. How will you take out the pins without dipping your hands into the water?
Answer:
If we keep a strong bar magnet above the glass of water, all pins inside the water come up and attract the magnet.

In-Text Activities
Activity 1
Question $1 .$
Take a magnet. Take the magnet Closer to the objects surrounding you.
What happens? Observe and note.
i. The objects attracted by the magnet:
ii. The objects, not attracted by the magnet:
iii. Which substance is used to make the objects attracted by the magnet?
Answer:
i. The objects attracted by the magnet: irons nail, iron rod, pins, needle, key, iron filings.
ii. The objects, not attracted by the magnets: rubber, paper, plastic pen, scale, pencil, water bottle.

iii. Which substance is used to make the objects attracted by the magnet?
Iron is used to make the objects attracted by the magnet.

Activity 2
LET US MAKE MAGNETS
Take a nail / a piece of Iron and place it on a table. Now take a bar magnet and place one of its poles near one edge of the nail/piece of Iron and rub from one end to another end without changing the direction of the pole of the magnet. Repeat the process for 30 to 40 times.

Bring a pin or some iron filings near the nail/piece of Iron to check whether it has become a magnet. Does the nail/piece of iron attract the pin/iron filings? If not, continue the same process for some more time.
Answer:
Yes, The nail / a piece of Iron acquires the same ability to attract other pieces of pin/ iron filings.

Activity 3
Make your own magnetic compass
Insert the magnetized needle, that you made in the activity 2 , in to two styrofoam balls and place the needle in bowl of water. Test whether the floating needle is always turned in rest on north-south direction.

Note : If you don't have styrofoam balls you can use dry leaf or a cork piece.

Inference: The floating needle is always turned in nest on North-South direction.

Additional Questions
I. Choose the appropriate answer:
Question 1.
__________made objects are attracted by magnets.
(a) Plastic
(b) Iron
(c) Glass
(d) Wax
Answer:
(b) Iron

Question $2 .$
Magnets lose their property if they
(a) heated
(b) dropped from a height
(c) hit with hammer
(d) all of these

Answer:
(d) all of these

Question $3 .$
__________poles repel to each other.
i. $\mathrm{N}-\mathrm{N}$
ii. $\mathrm{N}-\mathrm{S}$
iii. $\mathrm{S}-\mathrm{N}$
iv. $\mathrm{S}-\mathrm{S}$
(a) $\mathrm{i}$ and ii
(b) ii and iii
(c) iii and iv
(d) $\mathrm{i}$ and iv
Answer:
(d) $\mathrm{i}$ and iv

Question 4 .
When $\mathrm{N}$ pole of bar magnet is moved closer to the north pole of a magnet it will
(a) attract
(b) repel
(c) rotate
(d) none
Answer:
(b) repel

Question $5 .$
Electro magnetic trains can easily attain a speed of _________km per hour.
(a) 1200
(b) 600
(c) 100
(d) 800
Answer:
(b) 600

II. Fill up the blanks:
1. The magnetic Ore is called as_________
2. _________magnets do not have a definite shape.
3. Man-made magnets are called _________
4. A _________is an instrument which is used to find directions.
5 . _________will also get affected by magnetic field.
6. For a _________magnet a single piece of soft iron can be used as a magnetic keeper across the pole.

Answer:
1. magnetite
2. Natural
3. Artificial
4. compass
5. Cell phone
6. horse-shoe

III. True or False. If False, give the correct statement:
Question 1.
Magnetites are artificial magnets.
Answer:
False. Magnetites are natural magnets.

Question $2 .$
Cube shaped magnets are also available.
Answer:
False. Oval shaped, Disc shaped, Cylindrical shaped magnets are also available.

Question $3 .$
Substancess which are attracted by magnet are called non-magnetic substance.
Answer:
False. Substances which are attracted by magnets are called magnetic substance.

Question $4 .$
The end of the magnet that points to the north is called south pole.
Answer:
False. The end point of the magnet that points to the south is called south pole.

Question $5 .$
The compass has a magnetic needle that can rotate easily.
Answer:
True.

Question $6 .$
Magnets lose their properties if they are dropped from a height.
Ans:
True.

Question $7 .$
Proper storage can also cause magnets to lose their properties.
Answer:
False. Improper storage can also cause magnets to lose their properties.

Question $8 .$
Electro magnetic train is also called as flying train.
Answer:
True.

IV. Match the following :

Answer:
$\mathrm{I}-\mathrm{f}$
$\mathrm{II}-\mathrm{d}$
III - e
IV - b
$\mathrm{V}-\mathrm{c}$
$\mathrm{VI}-\mathrm{a}$.

V. Analogy:
Question 1.
Natural magnet: Magnetic stones.
Artificial magnet:________
Answer:
Bar magnet.
 

Question $2 .$
Magnetic substance : Attracted by magnets
Non magnetic substance :________
Answer:
Not attracted by magnets.

Question $3 .$
Repel to each other: Like poles.
Attract to each other :________

Answer:
Unlike poles.
 

Question $4 .$
Demagnetisation:________
Making magnets: Rubbing with one end to another end without changing direction.
Answer:
Hit with hammer
 

Question $5 .$
Electromagnet: Magnetic crane.
Ordinary magnet:________
Answer:
Mobile phone covers.

VI. Give Short Answer:
Question 1.
Give the different shapes of Artificial magnets.
Answer:
1. Bar magnet
2. Horseshoe magnet
3. Ring magnet
4. Needle magnet
5. Oval shape magnet
6. Disc shape magnet
7. Cylindrical shape magnet.

Question $2 .$
Differentiate magnetic and non-magnetic substance.
Answer:
Magnetic substance:
1. It is attracted by magnets
2. Ex: Iron, Cobalt, Nickel
Non-magnetic substance:
1. It is not attracted by magnets
2. Ex: Paper, Plastic, Glass
 

Question $3 .$
Define - Poles of a magnet.

Answer:
The attractive force of the magnet is very large near the two ends. These two ends are called poles of a magnet.

Question $4 .$
Give the properties of magnets.
Answer:
1. Like poles repel each other.
2. Unlike poles attract each other.

Question $5 .$
What are the objects affected by magnetic field?
Answer:
Cellphone, Computer and DVD are the objects affected by magnetic field.

Question $6 .$
Give any two tips to store bar magnets.
Answer:
1. Bar magnet should be kept in pairs with their unlike poles on the same side.
2. They must be seperated by a piece of wood and two pieces of soft iron should be placed across their ends.

VII. Answer in detail :
Question $1 .$
Give the uses of magnets.
Answer:
1. Magnets are used in speakers to power up.
2. Magnets are used in Ladies hand bags, Pencil boxes etc., to make a tight seal.

3. Magnets are also used in some door locks.
4. In home, magnets are used as magnetic toys, magnetic smiley stickers, magnetic Alphabet stickers to stick on the refrigerators.
5. Magnets are used to store data in computers.

Question 2 .
How will you make levitating propeller?
Answer:
1. Make a propeller from a $500-\mathrm{ml}$ plastic bottle. Make a hole in the bottle lid.
2. Screw the lid with the hole on a bottle half filled with sand. Press fit a stiff straw in the lid. Embed the straw in the sand to make it stand erect. Place a few ring magnets in the straw. Similar poles will repel each other.
3. Place two magnets each inside and outside the propellor lid. These magnets will automatically stick to each other.
4. Like poles repel and this levitates the bottle fan. The ceiling fan makes it spin.
5. Place the propeller on the stiff straw. The magnets in the straw and the propeller should repel each other. This will make the propeller levitate. On placing it under a ceiling fan the propeller will spin very fast.