Page 1 - Lesson Note- Introduction to Magnet ..
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SAI INTERNATIONAL SCHOOL

                                                        Class 6
                                                   Lesson Notes
                                                 Subject- Physics

                                       Ch. – Magnets and Their Effects
                                      Subtopic- Introduction to Magnets


               Magnet:
                     A magnet is an object that can attract objects made of substances such as
                       iron, nickel and cobalt.
                     The name magnet has been derived from magnetite.
                     Magnets are used in telephones, televisions, washing machines, electric
                       motors and many other devices.
                     The property of magnets to attract substances like iron, nickel and cobalt is
                       called magnetism.
                     The force of attraction exerted by the magnet on these substances is called
                       magnetic forces.
                     The region around the magnet where the influence of its magnetic force can
                       be felt is called magnetic field.
                     Magnetic field can be represented by magnetic lines of force.

               Magnetic and non-magnetic substances:
                     The substances that are attracted by a magnet are known as magnetic
                       substances.
                     For e.g. iron, cobalt and nickel are some familiar examples.
                     The substances that are not attracted by a magnet are known as non-
                       magnetic substances.
                     For e.g. copper, brass and wood are some examples.

               (Note:Magnetite is an ore. It is an oxide of iron with the chemical formula
               Fe 3O 4. It is the most magnetic substance of all naturally occurring minerals on
               the earth.)

               Natural and artificial magnets:
               There are two types of magnets- natural magnets and artificial magnets.

               Objects that are found in nature and exhibit the properties of a magnet. Like
               attracting magnetic substance are known as natural magnets.E.g. magnetite.

               Objects that are man-made and exhibit the properties of a magnet like attracting
               magnetic substance are known as artificial magnets.
               For e.g. bar magnet, horseshoe magnet etc.
               Artificial magnets are made in many shapes and sizes.
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