# Chapter 13 Fun with Magnets

• Magnet is the material or object which attracts iron towards it.
• The material which are attracted towards magnet called magnetic. For example: iron, cobalt etc.
•  The material which are not attracted towards magnet called non-magnetic. For example: plastic, non- metals etc.
• Magnets have two poles: one is North pole and other one is South pole.
• Opposite poles of magnets attracts each other and same poles repel each other.
• A magnet can be formed easily by rubbing iron pieces to a magnet. Then the iron pieces becomes a magnet by repeating the process of rubbing.
• Compass is a device which helps to find the direction and it shows all the directions.
• Magnet lose their property if it is heated or broken.

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### Exercise 1 ( Page No. : 134 )

•  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.