1. Fill in the blanks in the following
(i) Artificial magnets are made in different shapes such as ______bar magnet____,
___Horse shoe magnet_____ and _____cylindrical magnet_______.
(ii) The Materials which are attracted towards a magnet are called___Magnetic matials_____.
(iii) Paper is not a __magnetic____ material.
(iv) In the olden days, sailors used to find direction by suspending a piece of____natural magnet with thread_______.
(v) A magnet always has _______two___ poles.
2. State whether the following statements are true or false:
(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 East-West direction at any place. ( True)
(vii) Rubber is a magnetic material. ( False)
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.
Answer:
The blade of the sharpener is made up of magnetic materials( iron)
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 ___Repulstion______
N - S _ Attraction
S - N Attraction_________
____S_____ - S Repulstion
5. Write any two properties of a magnet.
Answer:
- 1. Magnet attracts iron, nickel, cobalt material
- 2. magnet has two poles; north and south.
6. Where are the poles of a bar magnet located?
Answer:
- Poles of the magnet are located in ends.
7. A bar magnet has no markings to indicate its poles. How would you find out near which end is its north pole located?
Answer:
- We hang bar magnets freely by using the thread, the end locating north would be the north pole and the other would be the south pole.
8. You are given an iron strip. How will you make it into a magnet?
Answer:
Rubbing one pole of bar magnet over the iron strip clockwise for 30-40 minutes will convert the iron strip into a magnet.
9. How is a compass used to find directions?
Answer:
- The compass has a magnetic needle and if we rotate the needle it would be settled along with facing north and south direction.
10. A magnet was brought from different directions towards a toy boat that has been floating in 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.
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
The boat moves towards the magnet if the north
pole of the magnet 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 of magnetic material
Boat floats without changing its direction Boat is made up of non-magnetic material
Answer:
Column I Column II
Boat gets attracted towards the magnet --> Boat is made of magnetic material
Boat is not affected by the magnet --> Boat is made up of non-magnetic material
The boat moves towards the magnet if the north
pole of the magnet 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
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