To find out magnetic field due to a circular wire loop carrying electric current take a circular wire and pass it through the centre of a horizontal sheet of cardboard. Connect the ends of wire to a battery. Sprinkle some iron fillings on the cardboard sheet and switch on the circuit to pass electric current through the wire. Now, tap the cardboard gently. On tapping, you will observe that the iron fillings arrange themselves around the wire in concentric circles.
On careful observation you will find that the magnetic lines of force produced at every point of the wire are circular near the wire and straight at the centre of the coil. The strength of magnetic field is more at the centre of the coil because all the lines of force aid each other at the centre of the coil.
Test Your Understanding and Answer These Questions:
- Describe the formation of magnetic field due to a circular wire carrying current.
- Draw a sketch of the pattern of magnetic field due to a current carrying circular wire.