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                                     SAI  INTERNATIONAL SCHOOL

                                               SESSION 2020-21
                                                    GRADE  -VI
                                                   GEOGRAPHY

                           CH-2 GLOBE:LATITUDES AND LONGITUDES



               SUB –TOPIC  :WHY DO WE HAVE STANDARD TIME?

               NOTES:


                     Local time of different places   in the same country vary .

                     Places on different meridians within the same country show different
                       local times.

                     This means large countries spreading latitudinally will face many
                       problems in terms of time.

                     Hence the concept of standard time was devised.

                     Though the difference of time is their within a country yet the local time
                       of the

                       Central meridian of a country was chosen as Standard time of that
                       country

                           for convenience.

                    In India the local time of Mirzapur near Allahabad 821/2°East is taken as
                      the standard time of our country or ISD( Indian Standard Time)


                      HAS THIS SOLVED TIME CONFUSION THROUGHOUT WORLD?

                    Countries having large latitudinal extent have more than one standard
                      time.

                       Eg: Russia  11    Canada  9

                TIME ZONES:

                    To avoid time confusion within a large country and throughout world the
                      concept of time zone was introduced.
                  
                    World is divided into 24 time zones of an hour each.
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