Main Points

Electromagnetism

  • Magnetic field can be represented as imaginary lines around the magnet.
  • When electric current flows through a straight conductor the magnetic field lines appear as imaginary concentric lines around the conductor.
  • Solenoid is composed of a coil of many turns of insulated copper wire; wrapped around a circular cylinder.
  • Electric motor is a device which works on the principle of effect of a magnetic field on a current-carrying conductor.
  • When a conductor is moved in a magnetic field or a magnet is moved in relation to a conductor, electric current is induced in the conductor.
  • Electric generator works on the principle of electromagnetic induction.
  • When the direction of electric current keeps on changing at frequent intervals, it is called alternating current or AC.

These main points are highly helpful for last minute preparation for examination. You can glance through them while going for examination. You can view them in the school bus, in car, in elevator, etc.