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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 olden days, sailors used to find direction by suspending a piece of ___________. (v) A magnet always has __________ poles. Ans: (i) Horse shoe, bar magnet and cylindrical Artificial magnets can be made by rubbing iron road to the magnet and it is of different shapes.
(ii) Magnetic The materials like copper, iron or metals attracted towards the magnet are called magnetic.
(iii) Magnetic It is not magnetic because paper is not a metal.
(iv) Magnet Because magnet shows two direction and contains two poles called: North and South.
(v) Two Magnet have two poles: one is North pole and other one is South pole.
Q2 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. Ans: (i) False This statement is incorrect because magnet always contains two poles: north and south.
(ii) False Artificial magnets are man- made.
(iii) True Yes, it is so because opposite poles attracts each other and similar poles repel each other.
(iv) False It is false because iron attracts towards the poles of magnet. So maximum iron fillings sticks at the poles of the magnet when it is brought near them.
(v) True Magnet has two poles. That’s why it always point towards 2 direction North and south.
(vi) True Yes, it is so because compass shows two directions: North and South. So, by knowing these two directions one can easily find out east west directions.
(vii) False Rubber is a non- magnetic material. It is not attracted towards magnet.
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: Pencil sharpener gets attracted by both the poles of magnet when it is placed near it because the blade of the sharpener is made up of iron which is a metal. As we know metal is attracted towards the magnet easily.
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. Column I Column II N - N _________ N - _________ Attraction S - N _________ _________ - S Repulstion Ans: Column I Column II
N – N Repulsion
N – S Attraction
S – N Attraction
S – S Repulsion
This is so because opposite poles of a magnet attract each other and the same poles of a magnet repel each other.
Q5 Write any two properties of a magnet. Ans: Two properties of a magnet are as follows:
- Opposite poles of a magnet attract each other and the same poles of a magnet repel each other.
- It attracts metal materials like iron, nickel, cobalt towards it.
- It helps to find out directions.
Q6 Where are poles of a bar magnet located? Ans: The two poles of a bar magnet are locked at the ends of the bar magnet. At the one end, North pole is present and at the other end South pole is present there.
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: We can find out the poles of a bar magnet by keeping them in air with the help of a thread. The one end which shows north direction is the north pole and the other one which shows south direction is south pole.
Second way to find out the poles of a bar magnet. Keep the bar magnets near each other. If both are repelling each other than we can find out that there poles are similar. If they both attracts each other then we can say their poles are on opposite direction because opposite attracts each other.
Q8 You are given an iron strip. How will you make it into a magnet? Ans: A iron strip can be converted into magnets by an experiment:
- Take an iron strip on the table.
- Take one magnet and rub this magnet over the iron with one end to each other.
- Repeat this process a number of times.
- After some time you will see that the iron strip is also behaving like a magnet. By this process we can make a magnet.
Q9 How is a compass used to find directions? Ans: Compass is a device in which one needle is present and two directions North and South are shown. When compass is kept in air then its needle shows the deflection towards the North, then this direction is north. If the needle shows deflection towards south then this direction must be south.
Q10 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. Column I Column II Boat gets attracted towards the magnet Boat is fitted with a magnet with north pole towards its head Boat is not affected by the magnet Boat is fitted with a magnet with south pole towards its head Boat moves towards the magnet if north Boat has a small magnet fixed along its length pole of the magnet is brought near its head Boat moves away from the magnet Boat is made of magnetic material when north pole is brought near its head Boat floats without changing its direction Boat is made up non-magnetic material Ans: Column I Column II
Boat gets attracted towards the magnet Boat is made up non-magnetic material
Boat is not affected by the magnet Boat is made up non-magnetic material
Boat moves towards the magnet if north Boat is fitted with a magnet with south pole towards its head. pole of the magnet is brought near its head
Boat moves away from the magnet Boat is fitted with a magnet with north pole towards its head when north pole is brought near its head
Boat floats without changing its direction Boat has a small magnet fixed along its length
The material which are attracted by magnet are called magnetic materials and which are not attracted by magnet called non- magnetic materials. Opposite poles of a magnet attracts each other like N- S, S- N etc. Same poles of a magnet repel each other like N- N, S-S etc.