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 1.
(i) Artificial magnets are made in different shapes such as bar magnets, horseshoe and cylindrical.
(ii) The Materials which are attracted towards a magnet are called magnetic.
(iii) Paper is not a magnetic material.
(iv) In the olden days, sailors used to find direction by suspending a piece of magnet.
(v) A magnet always has two poles.
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 the North-South direction.
(vi) A compass can be used to find the East-West direction at any place.
(vii) Rubber is a magnetic material.
Solution 2.
i) A cylindrical magnet has only one pole. False
ii) Artificial magnets were discovered in Greece. False
iii) Similar poles of a magnet repel each other. True
iv) Maximum iron filings stick in the middle of a bar magnet when it is brought near them. False
v) Bar magnets always point towards the North-South direction. True
vi) A compass can be used to find the East-West direction at any place. True
vii) Rubber is a magnetic material. 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: If it gets attracted by both the poles of a magnet then the material that might have been used to make some part of it is iron.
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.
| Column – I | Column – II |
| N-N | _______ |
| N-___ | Attraction |
| S-N | _____ |
| ___-S | Repulsion |
Solution 4.
| Column – I | Column – II |
| N-N | Repulsion |
| N- S | Attraction |
| S-N | Attraction |
| S– S | Repulsion |
Question 5. Write any two properties of a magnet.
Solution 5. The following are the properties of a magnet:
- A magnet attracts objects that are made up of Nickel, Cobalt and Iron.
- Two like poles s-s or n-n repel each other while two unlike poles like n-s attract each other.
- A suspended magnet always is in a north-south direction when it comes to rest.
Question 6. Where are the poles of a bar magnet located?
Solution 6. The poles of the bar magnet are located on its two ends.
Question 7. A bar magnet has no markings to indicate its poles. How would you find out near which end its north pole is located?
Solution 7. Suspend a bar magnet with the help of a thread when it comes to rest it would show a north-south direction. The end which shows the north direction will be the north pole.
Question 8. You are given an iron strip. How will you make it into a magnet?
Solution 8. Take an iron strip and place a magnetic bar in such a manner that one end of the iron strip and one end of the magnetic bar is in contact with each other.
Now follow the steps given below to turn the iron strip into a magnet:
- Without lifting the magnetic bar, move it along the length of the iron strip till you reach the other end.
- Lift the magnet and bring the same pole to the same end of the iron strip from which you began.
- Again, move the magnetic bar along the iron strip in the same direction as you did before.
- Repeat this process about 30-40 times.
- Now test your magnet by placing some iron fillings near the iron strips if it attracts the fillings then your magnetic iron strip is ready and if not then repeat this process until you get your magnet.
Question 9. How is a compass used to find directions?
Solution 9. A compass is a device which shows north and south direction. We can find all the directions by using it as a reference.
Question 10. A magnet was brought from different directions towards a toy boat that has been floating in water in a tub. 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.
| Column I | Column II |
| Boat gets attracted towards the magnet | Boat is fitted with a magnet with a north pole towards its head |
| Boat is not affected by the magnet | Boat is fitted with a magnet with a south pole towards its head |
| Boat moved towards the magnet when the north pole is brought near its head | Boat has a small magnet fixed along its length |
| Boat moves away from the magnet when the north pole is brought near its head | Boat is made up of magnetic material |
| Boat floats without changing its direction | Boat is made up of non-magnetic material |
Solution 10.
| Column I | Column II |
| Boat gets attracted towards the magnet | Boat is made up of magnetic material |
| Boat is not affected by the magnet | Boat is made up of non-magnetic material |
| Boat moved towards the magnet when the north pole is brought near its head | Boat is fitted with a magnet with a south pole towards its head |
| Boat moves away from the magnet when the north pole is brought near its head | Boat is fitted with a magnet with a north pole towards its head |
| Boat floats without changing its direction | Boat has a small magnet fixed along its length |