1) Take a wooden plank covered with white paper.
2) Make holes on its surface.
3) Pass copper wire through holes.
4) Join the ends of the coil to a battery through switch.
5) Current passes through the coil, when we switch on the circuit.
6) Now sprinkle iron fillings on the surface of the plank, around the coil. Then orderly pattern of iron fillings is seen on the paper.
7) The iron filings arrange themselves in orderly and look like lines of force.
8) The long coil is known as solenoid. The direction of the field due to solenoid is determined by using right hand rule.
9) One side of the solenoid behaves like north pole and the other side behaves like south pole.
10) Outside the solenoid the direction of lines of force are from north to south while inside the direction is from south to north. Thus the magnetic field lines are closed loops.
11) Hence electric charges in motion produce magnetic field.