📚 NCERT Questions — Exploring Magnets
Q1. Fill in the blanks: (a) Artificial magnets are made in different shapes such as _________, _________ and _________. (b) The materials which are attracted towards a magnet are called _________ materials. (c) Paper is not a _________ material. (d) In olden days, sailors used to find direction by suspending a piece of _________. (e) A magnet always has _________ poles.
Solution dekho
(a) Artificial magnets are made in different shapes such as bar magnet, horseshoe magnet and cylindrical magnet. (b) The materials which are attracted towards a magnet are called magnetic materials. (c) Paper is not a magnetic material. (d) In olden days, sailors used to find direction by suspending a piece of magnet. (e) A magnet always has two poles.
Q2. State whether the following statements are True or False: (a) A cylindrical magnet has only one pole. (b) Artificial magnets were discovered in Greece. (c) Similar poles of a magnet repel each other. (d) Maximum iron filings stick in the middle of a bar magnet when it is brought near them. (e) A compass can be used to find East-West direction at any place. (f) Rubber is a magnetic material.
Solution dekho
(a) False (A cylindrical magnet, like all magnets, has two poles: North and South.) (b) False (Natural magnets (lodestones) were discovered in Greece, artificial magnets were developed later by humans.) (c) True (Like poles repel each other.) (d) False (Maximum iron filings stick at the ends (poles) of a bar magnet, not in the middle.) (e) True (A compass needle aligns North-South, from which other directions like East and West can be determined.) (f) False (Rubber is a non-magnetic material.)
Q3. It is 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 dekho
A pencil sharpener's body is made of plastic, which is a non-magnetic material. However, the blade inside the sharpener is typically made of steel or iron, which are magnetic materials. Since steel/iron is attracted by a magnet, the sharpener gets attracted by both poles of a magnet.
Q4. Column I shows different positions in which one pole of a magnet is placed near that of another. Column II shows the resulting action between them. Fill in the blanks. Column I (Position of poles) (a) N-N (b) N-? (c) S-N (d) ?-S Column II (Action) (a) Repulsion (b) Attraction (c) ? (d) Repulsion
Solution dekho
Column I (Position of poles) (a) N-N (b) N-S (c) S-N (d) S-S Column II (Action) (a) Repulsion (b) Attraction (c) Attraction (d) Repulsion
Q5. Write any two properties of a magnet.
Solution dekho
Two properties of a magnet are: 1. A magnet always has two poles: a North pole and a South pole. 2. Like poles repel each other, and unlike poles attract each other. (Other valid properties: A freely suspended magnet always aligns in the North-South direction; Magnets attract magnetic materials.)
Q6. Where are the poles of a bar magnet located?
Solution dekho
The poles of a bar magnet are located at its two ends. These are the regions where the magnetic force is the strongest.
Q7. A bar magnet has no markings to indicate its poles. How would you find out near which end is its North pole located?
Solution dekho
To find the North pole of an unmarked bar magnet, you can suspend it freely from its center using a thread. Allow it to come to rest. The end of the magnet that points towards the geographic North direction will be its North pole.
Q8. You are given an iron strip. How will you make it into a magnet?
Solution dekho
To make an iron strip into a magnet, you can use the single touch method: Take a bar magnet and place one of its poles (say, North pole) at one end of the iron strip. Without lifting the magnet, rub it along the length of the iron strip towards the other end. Lift the magnet and bring the same pole back to the starting point of the iron strip. Repeat this process about 30-40 times, always rubbing in the same direction and using the same pole. After some time, the iron strip will become a magnet. The end where you finished rubbing will acquire the opposite polarity to the pole of the magnet used for rubbing.
Q9. How does a compass work?
Solution dekho
A magnetic compass works on the principle that a freely suspended magnet always aligns itself in the North-South direction. A compass contains a small, lightweight magnet (the needle) pivoted at its center, allowing it to rotate freely. The Earth itself acts like a giant magnet, creating a magnetic field. When the compass is held steady, its magnetic needle aligns with the Earth's magnetic field, with its North-seeking pole pointing towards the Earth's geographic North direction and its South-seeking pole pointing towards the Earth's geographic South direction. This allows users to determine directions.
Q10. Why is repulsion a surer test of magnetism than attraction?
Solution dekho
Repulsion is considered a surer test of magnetism than attraction because: 1. A magnet attracts magnetic materials (like iron, nickel, cobalt) as well as other magnets. So, if an object is attracted to a magnet, it could either be a magnetic material or another magnet. 2. However, repulsion only occurs between two magnets when their like poles are brought near each other. A non-magnetic material will never be repelled by a magnet. Therefore, if an object is repelled by a known magnet, it confirms that the object itself is also a magnet.