To observe the magnetic field lines around current carrying conductor.
- Magnetic effect of electric current is one of the major effects of electric current in use, without the applications of which we cannot have motors in the existing world.
- A current carrying conductor creates a magnetic field around it, which can be comprehended by using magnetic lines of force or magnetic field lines.
- The nature of the magnetic field lines around a straight current carrying conductor is concentric circles with centre at the axis of the conductor.
- The strength of the magnetic field created depends on the current through the conductor.
- The direction of the magnetic field lines of force around a conductor is given by the Maxwell’s right hand grip rule or the right handed corkscrew rule. Imagine that you are holding a current-carrying straight conductor in your right hand such that the thumb points towards the direction of current. Then your fingers will wrap around the conductor in the direction of the field lines of the magnetic field (See Fig.1). This is known as right hand thumb rule.
Fig 1 - Right hand thumb rule.