Q1. 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 the olden days, sailors used to find direction by suspending a piece of ______.
(v) A magnet always has ______ poles.
Ans:
(i) Artificial magnets are made in different shapes such as bar-magnet, cylindrical magnets and horseshoe magnets.
Cylindrical magnet(ii) The Materials which are attracted towards a magnet are called magnetic materials.
(iii) Paper is not a magnetic material.
(iv) In the olden days, sailors used to find direction by suspending a piece of bar magnet.
(v) A magnet always has two poles.
Magnet having two poles (North & South)Q2. State whether the following statements are true or false.
Question for NCERT Solutions: Fun With Magnets
Try yourself:(i) A cylindrical magnet has only one pole.
Explanation
A magnet of any shape always has two poles; North pole and south pole. Magnets of any shape have two poles because magnetic field lines are continuous and always form closed loops. The poles of a magnet are the places on the surface where the looping field lines emerge from and re-enter the magnetic material.
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Question for NCERT Solutions: Fun With Magnets
Try yourself:(ii) Artificial magnets were discovered in Greece.
Explanation
Artificial magnets were not discovered in Greece. Instead, natural magnets (lodestones) were discovered in ancient Greece. Artificial magnets are man-made and were developed later through scientific processes.
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Question for NCERT Solutions: Fun With Magnets
Try yourself:(iii) Similar poles of a magnet repel each other.
Explanation
When two magnets are placed with their like poles facing each other, the lines of force from each magnet are in opposite directions, causing them to repel.
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Question for NCERT Solutions: Fun With Magnets
Try yourself:(iv) Maximum iron filings stick in the middle of a bar magnet when it is brought near them.
Explanation
Maximum iron filings will stick to the ends of the bar magnet because at the ends of the magnet poles are located. The strength of the poles is maximum at the ends of the magnet.
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Question for NCERT Solutions: Fun With Magnets
Try yourself:(v) A freely suspended Bar magnets always point towards North-South direction.
Explanation
Yes, a freely suspended bar magnet always points in the north-south direction.
A bar magnet's north pole is attracted to the earth's magnetic south pole, and its south pole is attracted to the earth's magnetic north pole. This causes the magnet to align itself in the north-south direction.
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Question for NCERT Solutions: Fun With Magnets
Try yourself:A compass can be used to find East-West direction at any place.
Explanation
Always the needle of the compass points towards North-South direction. So if North-South direction is known then East-West direction can also be known.
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Question for NCERT Solutions: Fun With Magnets
Try yourself:(vii) Rubber is a magnetic material.
Explanation
False: Rubber is not a magnetic material because it lacks the properties necessary for magnetism. Magnetism is primarily associated with materials that have magnetic domains, which are regions where the magnetic moments of atoms or molecules are aligned in the same direction.
Rubber, being a non-metal and a non-magnetic material, does not have magnetic domains, and its molecular structure does not exhibit magnetic properties. In contrast, magnetic materials like iron, nickel, and cobalt have atoms with magnetic moments that can align and create magnetic domains, allowing them to be attracted to magnets.
In summary, the absence of magnetic properties in rubber is due to its molecular structure, which does not support the formation of magnetic domains.
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Q3. 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.
Ans: There is a blade in pencil sharpener which is made up of iron. Iron is a magnetic material that is why it is attracted by the poles of magnet.
Q4. 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.
Ans:
Q5. Write any two properties of a magnet.
Ans: Two properties of a magnet are as follows:
(i) Like magnetic poles repel each other and unlike magnetic poles attract each other.
(ii) A freely suspended magnet always aligns in N-S direction.
Q6. Where are poles of a bar magnet located?
Ans: The poles of bar magnet are located at its two end points.
Two Poles
Q7. A bar magnet has no markings to indicate its poles. How would you find out near which end is its north pole located?
Ans:
- The location of the poles of a magnet can be determined by suspending it freely.
- A freely suspended bar magnet always points in the north−south direction.
- The end that points towards the north direction is the north pole of the magnet while the end that points towards the south direction is the south pole of the magnet.
Q8. You are given an iron strip. How will you make it into a magnet?
Ans: An iron strip can be converted into a magnet by the following method:
- Place the iron strip on a table.
- Place one pole of a bar magnet near one end of the iron strip. Move the bar magnet along the length of the iron strip starting from one end to the other end as shown in the following figure.
- Then, lift the magnet and bring the pole to the starting point and move in the same direction as before.
- On repeating this process for at least 30-40 times, the iron strip will become a bar magnet with two poles.
Q9. How is a compass used to find directions?
Ans:
- A compass has a magnetic needle that can rotate freely.
- When a compass is kept at a place, the magnetic needle aligns in north-south direction.
- The red arrow of the compass needle is termed as the north pole and the other end as south pole.
A Compass
Q10. A magnet was brought from different directions towards a toy boat that has been floating on water in a tub. The effect 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.
Ans: