(1) Take a wooden plank and make a hole as shown in figure. Place this plank on the table.
(2) Now place a retort stand on the plank as shown in figure.
(3) Pass a 24 gauge copper wire through hole of the plank and rubber knob of the retort stand in such a way that the wire be arranged in a vertical position and not touch the stand.
(4) Connect the two ends of the wire to a battery via switch.
(5) Place 6 to 10 compass needles in a circular path around the hole so that its centre coincides with the hole.
(6) Use a 9V battery in the circuit. Switch on current flows through the wire.
(7) We notice that they are directed as tangents to the circle.
(8) The magnetic field around the wire is circular in shape. This can be verified by sprinkling iron filings around the wire when current flows in the wire.
(9) The direction of magnetic field around the wire will be as shown in the following figure.
(10) The direction of the magnetic field around the current carrying wire can be determined by right hand thumb rule i.e., grab the current carrying wire with your right hand in such a way that thumb is in the direction of current, then the curled fingers show the direction of magnetic field as shown in the figure.
