Class:- 6, Science, Chapter:- 13 (Fun With Magnets) Notes, NCERT Solutions & Frequently Asked Questions

 Science

Class:-6, Chapter:- 13

(Fun With Magnets)

Notes, NCERT Solutions & Frequently Asked Questions

-- Notes --

⭐ Magnet:- Objects, which attract magnetic materials like cobalt, nickel and iron are called as a magnet.

Note:- The ancient, elderly, Greek shepherd was the first person to discover mineral. It is a naturally occurring mineral called magnetite. Therefore, this naturally occurring mineral – magnet was named by the discoverer’s name. 

• The magnets, obtained naturally from a Magnetite rock, are called as the natural magnets.

• The magnets prepared by the combination of certain mineral ores are called as the artificial magnets.

⭐ Magnetic Materials:- Materials easily attract by a magnet are called magnetic materials. 

• Eg.- Cobalt, nickel and iron etc. 

⭐ Non-magnetic Materials:- The materials which are not attracted by the magnet even when they are brought closer to the magnets are called the Non-magnetic Materials. 

• Eg.- Aluminium, zinc, wood, and rubber

⭐ Types of Magnets:- Magnets are classified based on their shapes. The different types of magnets include – bar magnet, dumb-bell shaped magnet, horseshoe magnet, cylindrical magnet, etc.

⭐ Magnetic compass:- The magnetic compass is a simple device, which is composed of a small box with a glass top and a magnetic needle, which moves and indicates the directions.

⭐ Discovery of Magnets:- Greeks used the term magnet in six hundred B.C. for the mysterious stone that seemed to attract iron and other materials. It was first discovered by a Greek shepherd named Magnes (hence the terminology), when his stick that had an iron end got stuck to a rock.

⭐ Properties of magnets:- These are the magnet's main properties:- 

• Magnets attract magnetic materials.

• The like poles repel each other, whereas the unlike poles attract one other.

• A hung magnet always comes to rest facing north-south.

• The magnet's poles are arranged in pairs. i.e. magnetic monopole doesn't exist.

⭐ Poles of a Magnet:- Every magnet is bipolar (they have 2 poles at the extremities). 

• This can be seen by spreading iron filings around a magnet. These filings arrange themselves in a pattern which is mostly dense towards the two ends of a magnet. 

• These poles are called North and South poles of a magnet.

⭐ Magnetic poles of the Earth:- 

• Earth has 2 geographic poles, north and south poles.

• They are the Arctic (South pole of the earth’s magnet) and Antarctica (North Pole of the earth’s magnet).

• Earth’s magnetic poles are near but not exactly in the same place as the geographic poles.

• A magnetic compass aligns itself towards the magnetic north pole of the earth.

⭐ Using magnets to find directions:- When a bar magnet is suspended freely by a thread, it aligns itself to the direction of North.

• Travellers have used this property of magnets for ages to find directions.

⭐ Making a magnet:- The magnetic material can be made into a magnet by rubbing a magnet on the surface of the magnetic material.

• This creates an influence, where the particles inside the material align themselves like the poles of a magnet.

⭐ Microscopic cause of magnetism:- 

• Each particle in a magnetic material behaves somewhat like a bar magnet.

• They are normally aligned randomly within the material.

• But under the influence of a stronger magnet, they realign themselves according to the stronger magnet’s field.

⭐ Loss of magnetic property:- The magnetic property of a magnet is lost on:-

• Heating

• Hammering or hitting

• Dropping

⭐ Attraction and Repulsion between Magnets:- 

• Like poles repel each other. 

• Unlike poles attract each other.

⭐ Inseparable Poles:- 

• Magnetic poles always exist in pairs. If you cut a bar magnet in half, it forms 4 poles, each half having a north and a south pole.

• The two poles of a magnet repel when their like poles face each other and attract each other when unlike poles are brought near. These two poles of a magnet are called as ‘inseparable poles’.

-- NCERT Solutions -- 

Question 1.- Fill in the blanks in the following:-

i) Artificial magnets are made in different shapes such as __________, __________ and ____________.

ii) The Materials which are attracted towards a magnet are called________.

iii) Paper is not a ______ material.

iv) In olden days, sailors used to find direction by suspending a piece of ___________.

v) A magnet always has __________ poles.

Solution:-

i) bar magnet, horse shoe and cylindrical.

ii) magnetic.

iii) magnetic 

iv) magnet.

v) two 

Question 2.- State whether the following statements are true or false:-

i) A cylindrical magnet has only one pole.

ii) Artificial magnets were discovered in Greece.

iii) Similar poles of a magnet repel each other.

iv) Maximum iron filings stick in the middle of a bar magnet when it is brought near them.

v) Bar magnets always point towards North-South direction.

vi) A compass can be used to find East-West direction at any place.

vii) Rubber is a magnetic material.

Solution:-

i) False

ii) False

iii) True

iv) False

v) True 

vi) True

vii) False

Question 3.- It was observed that a pencil sharpener gets attracted by both the poles of a magnet although its body is made of plastic. Name a material that might have been used to make some part of it.

Solution:- Iron might have been used to make some part of it.

Question 4.- Column I shows different positions in which one pole of a magnet is placed near that of the other. Column II indicates the resulting action between them for each situation. Fill in the blanks.

Solution:- 

Question 5.- Write any two properties of a magnet.

Solution:- Properties of a magnet are as follows

      • It attracts objects made of Nickel, Cobalt and Iron.

      • Like poles of two magnets repel each other and opposite poles attracts each other.

Question 6.- Where are poles of a bar magnet located?

Solution:- On two ends of a bar magnet.

Question 7.- A bar magnet has no markings to indicate its poles. How would you find out near which end is its north pole is located?

Solution:- A bar magnet is hanged in the air and the end pointing to the north is the north pole of the magnet.

Question 8.- You are given an iron strip. How will you make it into a magnet?

Solution:- Take a bar magnet and keep in contact with one of its poles with one edge of the bar of iron.

• Without lifting the bar magnet, move it along the length of the iron bar till you reach the other end.

• Lift the magnet and bring the pole (the same pole you started with) to the same point of the iron bar from which we began.

• Move the magnet again along the iron bar in the same direction as you did before.

• Repeat this process for about 30-40 times.

Question 9.- How is a compass used to find directions?

Solution:- A compass always shows north and south direction, by keeping this as a reference we can always find east and west directions also.

Question 10.- A magnet was brought from different directions towards a toy boat that has been floating in water in a tub. Affect observed in each case is stated in Column I. Possible reasons for the observed effects are mentioned in Column II. Match the statements given in Column I with those in Column II.

Solution:- 

-- Frequently Asked Questions -- 

Question 1.- How can you separate a magnetic substance from a mixture?

Solution:- By using a bar magnet, the magnetic substance is separated from mixture.

Question 2.-  At which place on a magnet, its magnetic force is maximum?

Solution:- At poles.

Question 5.- In which direction does a suspended magnet come to rest?

Solution:- Magnet comes to rest in N-S (north-south) direction.

Question 6.- What happens when N-pole of a magnet is brought near the N-pole of a suspended magnet?

Solution:- There is repulsion between these two magnets as there is repulsion between like poles.

-- By Durgesh Pandey