Electromagnetic Induction

• Permanent magnets: The substances that retain their ferromagnetic property at room temperature for a long period of time are called permanent magnets.
• Electromagnets: Electromagnet is a magnet consisting of soft iron core with a coil of insulated wire wound round it. When a current flows through the wire, the core becomes magnetized.
• Solenoid: It is consist of an insulating long wire wound in the form of helix. Its length is very large as compare to the its diameter. 

• A current carrying the rod experiences a force when placed between two poles of strong magnets. The direction of force exerted on the rod is related with the direction of current. 
• Magnitude of magnetic force depends upon three factors:
   
  $\left(1\right) F\propto I (\dots$