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GURUKUL CENTRAL ACADMY, CH- 14- FUN WITH MAGNETS, WORKSHEET-1, Refer to textbook, WORKSHEET-2, Refer to textbook, WORKSHEET-3, A. earth, magnet, south, compass, field, north, B. a phenomenon, electromagnetism, temporary, C. 1. Magnetic compass, 2. Pilots and navigators 3. To find the direction, 4. Aluminium box, a sharp needle, a magnetic needle, , EXERCISES, A. 1. d. 2. c. 3. d. 4. d. 5. a. 6. b. 7. b. 8. b. 9. b. 10. d., B. 1. True, 4. False, C. 1. – e., , 2. False, 5. False, 2. – a., , d. 1. Magnetic, 2. Non-magnetic, 3. Non-magnetic, 4. Non-magnetic, 5. Magnetic, 6. Magnetic, , 3. False, 6. True, 3. – b. 4. – c., , 5. – d.

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GURUKUL CENTRAL ACADMY, e. 1. Black rock having magnetic property., 2. North Pole, 3. No, 4. No, 5. No, 6. Computer, ATM card and generator, f. 1. Temporary and permanent magnets., 2., , Natural Magnet: Magnet which is found in nature is called, natural magnet. This magnet has a low magnetic power., Artificial Magnet: Magnet which is prepared by human is called, artificial magnet. This magnet is much stronger than natural, magnet., , 3., , Magnetic Material: Materials which are attracted by a magnet, are called magnetic materials. Cobalt, iron and nickel are, magnetic materials., Non-magnetic Material: Materials which are not attracted by a, magnet are called non-magnetic materials. Wood, plastic and gold, are non-magnetic materials., , 4., , A magnet can lose its magnetism, due to the following, reasons. • Falling from a height • Hitting with a hammer, • Heating above a certain temperature • Not storing, Properly, , 5., , A magnetic compass is a simple device used by the pilots and, navigators to find the direction in which their aeroplane or ship is, going.

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GURUKUL CENTRAL ACADMY, 6., , Each small piece acts as a complete magnet with two poles., , 7., , Magnets formed due to electricity are electromagnets., , g. 1. Refer Activity 4 from page 156., 2., , Refer Activity 6 from page 158., , 3., , Refer Activity 2 from page 155., , 4., , A magnet should be stored properly so that it does not lose its, properties. To preserve magnetism for a long time, magnets are, stored in magnetic keepers. The bar magnets should be stored in, pairs in a wooden box, separated by a piece of wood, such that, their opposite ends face each other. Furthermore, pieces of iron, should be placed at both the ends. In case of a horse-shoe magnet, a piece of soft iron should be placed at its ends. This piece of iron, will stick to its ends and prevent the loss of magnetism., , 5., , A magnetic compass consists of a flat circular aluminium box at, the base of which are marked directions like north, south, east,, west, north-east, north-west, etc. From its centre, rises a sharp, needle, over which is placed a magnetic needle. The magnetic, needle, completely free to move in any direction, always rests in, the north-south direction. By looking at the north pole of the, magnetic needle we can find the given direction., , 6., , • You can use a magnet to find a pin/needle dropped on, the floor or in other place., • Magnets are used in Magnetic recording devices. Computers, and hard disks record data on a thin magnetic coating.

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GURUKUL CENTRAL ACADMY, •, , •, , 7., , Magnetic strips present on ATM and debit cards store the users’, account information and help in money transaction., Magnets are used in the doorbells, speakers, microphones,, electric motors and generators., • Magnets are also employed in children’s toys., , i. Magnets exert more magnetic force at the ends as compared to, the middle., ii. A magnet always comes to rest in north-south direction., iii. Like poles repel, unlike poles attract each other., iv. Magnetic poles always exist in pairs., , 8., , Electromagnets are temporary magnets as they lose their, magnetism when the current stops flowing through them.