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SAI International School
                                                      Class VII
                                                   Lesson Notes
                                                 Subject: Physics
                                   Ch- Electric current and simple circuit
                                   Subtopic: Magnetic effects of Current


          MAGNETIC   EFFECTS   OF   ELECTRIC   CURRENT:

          When electric current passes through a conducting wire, it behaves as a magnet. This is known as
          magnetic effect of electric current.
          Hans Christian Oersted was the first to observe this phenomenon in1820.
                   Magnet attracts substances made from magnetic materials like iron, nickel and cobalt
                   A current carrying conductor acts as a magnet with magnetic field around it.
                   The strength of magnetic field depends upon the amount of current passing through it.
                   A magnetic field around a current carrying wire is in concentric circles and direction is
                     given by Maxwell’s right hand thumb rule.
                   The direction of magnetic field can be reversed by changing the direction of the current
                     in the wire


















                   The deflection in magnetic compass can be increased by increasing the amount of
                     current (means magnetic strength can be increased with increased current).


              ELECTROMAGNET
              Electromagnet is a device consisting of a coil of insulated wire wrapped around an iron core

              that becomes magnetized when an electric current flows through the wire.
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