Question

Draw a labelled diagram of an electric bell and explain its working.

Answer

labelled diagram of an electric bell

DAV Class 7 Science Chapter 17 Solutions
labelled diagram of an electric bell

Working of an electric bell

  • When current flows through the electromagnet it acquires magnetism and attract the armature.
  • As the armature bends towards the electromagnet, the gong is struck. But at the same time contact between armature and contact screw gets broken and the circuit gets switched off.
  • As the current flow stops, the electromagnet loses it magnetism. It, therefore, no longer attracts the armature.
  • The armature gets pulled back to its original position by spring action. It, now, again comes in contact with the contact screw; the circuit gets completed again. The cycle repeats itself and the gong gets struck again. This, in turn, again breaks the circuit.