Chapter 13 Fun with Magnets
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.
Answer:
i) Artificial magnets are made in different shapes such as bar magnet, cylindrical and horse shoe.
ii) The Materials which are attracted towards a magnet are called magnetic.
iii) Paper is not a magnetic material.
iv) In olden days, sailors used to find direction by suspending a piece of magnet.
v) A magnet always has 2 (North and South) 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 North-South direction.
vi) A compass can be used to find East-West direction at any place.
vii) Rubber is a magnetic material.
Answer:
i) False
ii) False
iii) True
iv) False
v) True (It happens only when it is freely suspended)
vi) True
vii) 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.
Answer: A 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.
N - N = Repulsion
N - S = Attraction
S - N = Attraction
S - S = Repulsion
Question 5: Write any two properties of a magnet.
Answer: The two properties of a magnet are
→ It attracts objects made of metal like cobalt, nickel etc.
→ Like poles of two magnets repel each other and opposite poles attracts each other.
Question 6: Where are poles of a bar magnet located?
Answer: The poles of a bar magnet are located at its 2 ends.
Question 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 can find out which end is bar magnet is north pole by taking that bar magnet and suspending it freely with help of a thread, the end that points towards north pole will be regarded as north end of the magnet.
Question 8: You are given an iron strip. How will you make it into a magnet?
Answer: First we have to take the iron strip. Then place it on the table. Now take a bar magnet and place one of its poles near one edge of the bar of iron. Without lifting the bar magnet, move it along the length of the iron bar till we reach the other end. Now, lift the magnet and bring the pole (the same pole we started with) to the same point of the iron bar from which we began. We have to move the magnet again along the iron bar in the same direction as we did before. Then we have to repeat this process about 30-40 times. And finally bring a pin or some iron filings near the iron bar to check whether it has become a magnet. If not, continue the process for some more time.
Question 9: How is a compass used to find directions?
Answer: A compass is used to find direction as a compass always shows north and south direction, by keeping this as a reference, east and west directions can also be found.
Question 10: A magnet was brought from different directions towards a toy boat that has been floating in water in a tub. Affect observed in each case is stated in Column I. Possible reasons for the observed affects are mentioned in Column II. Match the statements given in Column I with those in 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 the 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
No comments:
Post a Comment