How is the magnetic field pattern around a straight conductor?

The magnetic field pattern around a straight conductor is circular, with the conductor at the centre.

When a current passes through a straight conductor, it generates a magnetic field around it. This magnetic field is not random but follows a specific pattern. It forms concentric circles around the conductor, with the conductor itself being at the centre. The direction of the magnetic field is given by the right-hand grip rule. If you grip the conductor with your right hand and your thumb points in the direction of the current, your fingers will curl in the direction of the magnetic field.

The strength of the magnetic field is directly proportional to the current flowing through the conductor. This means that if the current is increased, the magnetic field becomes stronger. Conversely, if the current is decreased, the magnetic field becomes weaker. The strength of the magnetic field also decreases as you move further away from the conductor. This is because the magnetic field lines are more spread out at greater distances from the conductor.

The magnetic field pattern can be visualised using a simple experiment involving a straight conductor, a compass and a power source. When the current is switched on, the compass needle, which aligns itself with the magnetic field, will move. This shows that a magnetic field has been created. By moving the compass around the conductor, you can trace out the circular magnetic field lines.

In summary, the magnetic field pattern around a straight conductor is circular, with the conductor at the centre. The strength and direction of the magnetic field are determined by the current flowing through the conductor. This fundamental concept is crucial in understanding many phenomena in electromagnetism and plays a key role in the design of many electrical devices.