Magnetic Field and Field Lines
A magnetic field is a force field which is created by magnetic dipoles and moving electric charges, and it exerts a force on other nearby moving charges and magnetic dipoles. Magnetic Field is a vector quantity because it has both magnitude and direction.
Magnetic Field Lines
A magnetic field line or lines of forces shows the strength of a magnet and the direction of a magnet’s force. It was discovered by Michael Faraday to visualize magnetic field.
Direction of Field Lines
Magnetic field lines are directed from south pole to north pole inside the magnet and from north pole to south pole outside the magnet.
Strength of Magnetic Field Lines
A straight current carrying conductor has a magnetic field in the shape of concentric circles around it.The magnetic field of a straight current carrying conductor can be visualised by magnetic field lines.
The direction of a magnetic field produced due to a current carrying conductor rely upon the same direction in which the current is flowing
The direction of electric field gets reversed if the direction of electric current changes.
Let us understand this using a simple experiment
Suppose a straight current carrying conductor is hung vertically, and electric current is flowing from north to south i.e from up to down. In this situation, the direction of magnetic field will be clockwise. And if the same current is flowing from south to north through the same conductor, the direction of magnetic field will be anti-clockwise.
The direction of magnetic field in an electric current through a straight conductor can be represented by using Right-Hand Thumb Rule.
Right-Hand Thumb rule
Assume that you are holding a straight current carrying 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 field lines of the magnetic field.
Right Hand Thumb rule is also known as Maxwell’s corkscrew rule. If we consider ourselves driving a corkscrew in the direction of the current, then the direction of the corkscrew is in the direction of the magnetic field.
Magnetic Field Due to Flow of Current through a Circular Loop
The magnetic field produced in a circular current carrying conductor is the same as that of the magnetic field due to a straight current carrying conductor and the current carrying circular loop will behave like a magnet.
The magnetic field lines in a current carrying circular loop would be in the shape of concentric circles, and at the centre of the circular wire, field lines will become straight and perpendicular to the plane of coil.
The direction of magnetic field in a circular loop can be recognized using Right Hand Thumb Rule
Magnetic Field due to flow of current in a Solenoid
A solenoid is a tightly wound helical coil of wire whose diameter is small compared to its length.
Magnetic field produced by the current carrying solenoid is similar to a bar magnet. One end of a solenoid behaves as a south pole and the other end behaves as a north pole. The magnetic field produced inside a solenoid are parallel which is similar to a bar magnet.
The strong magnetic force produced by a solenoid can be used to magnetise a piece of magnetic material. The magnet so formed is known as an electromagnet.
Direct Current is the unidirectional flow of electric current. The flow of current in direct current does not change periodically. In case of a direct current, the current flows in a single direction at a steady voltage.
Direct current power is widely used in low voltage applications such as charging batteries, light aircraft electrical systems.
By using a rectifier a direct current can be obtained from an alternating current. A rectifier contains electronic elements or electromechanical elements that allow current to flow only in one direction.
Direct current can also be converted into alternating current by using motor generator set or by an inverter.
Study more about electromagnetism, Fleming’s left hand rule and right hand rule at BYJU’S
The direction of magnetic field in an electric current through a straight conductor can be represented by using Right Hand Thumb Rule.