NCERT 6th Class (CBSE) Science: Fun with Magnets

Question: Write main properties of a magnet.

Answer:

1.  Magnet has two poles—south pole and north pole.
2.  Poles of magnet cannot be isolated.
3.  Like poles repel each other and unlike poles attract each other.
4. Freely suspended magnet aligns in N-S direction.

Question: Write two methods by which a magnet can be demagnetised.

Answer:

1.  By hammering the magnet strongly.
2.  By heating a magnet strongly and keeping it in the east-west direction.

Question: It is advised to keep the magnets away from television, mobiles, CD and computers Explain why?

Answer: Television, mobiles, CD, computers and many more devices are made up of magnetic materials and magnets in it. If you bring a magnet closer to it then it will spoil these devices.

Question: Few iron nails and screws got mixed with the wooden shavings while a carpenter was working with them.How can you help him in getting the nails and screws back from the scrap without wasting his time in searching with his hands?

Answer: With the help of a magnet we can attract all iron nails and screws and can separate them from the wooden shavings. As iron nails and screws are magnetic materials and will get attracted to the agent, whereas wooden shavings are non-magnetic.

Question: It is said that repulsion is a sure test for magnetism. Why is it so?

Answer: To identify the magnet, repulsion (like poles of two magnets repel) is the only test which will let you know whether the given rod is an iron rod or a bar magnet. Because a magnet attracts an iron object and unlike poles of magnets also attract each other.

Question: A given bar magnet was broken into pieces. Where will be its North and South pole?

Answer: If you cut a bar magnet into pieces then the end labelled as North remains north and the other end formed will be south. Similarly the end that was pointing south will be south pole and its opposite end will be the new north pole.

Question: You are given two rods. Out of these, one is an iron rod and the other one is magnet, how will you identify these rods?

Answer: Take both the rods and suspend them separately. Bring one end of a bar magnet close to both the ends of the suspended rod. If it shows attraction at both the ends then it is an iron rod. If it shows attraction at one end and repulsion at the other end then it is a bar magnet.

Question: Explain briefly how you would classify objects as magnetic or non-magnetic if  you are give a bar magnet.

Answer: Magnet are made of materials that attract mad of certain substance like iron, cobalt and nickel. Magnets come in various shapes and sizes. They can be found as horseshoe, ring, cylindrical or bar shape. Not all objects are attracted to magnets. Objects that are attracted by a magnet are said to be magnetic, Eg: iron and nickel. Objects that are not attracted by a magnet, are said to be non-magnetic, Eg: wood and plastic.