Science class 10: Magnetic Effects of Electric Current

Introduction – Magnetic Effects of Electric Current

Electricity and magnetism are closely related. A magnetic effect is created when an electric current travels through copper wire. Hans Christian Oersted was the first to detect the Magnetic Effects of Electric Current. The magnetic field is a force which is created by magnetic dipoles and from moving electric charges, and due to the magnetic field, it exerts the forces in the nearby moving charges. The magnetic field has both direction and magnitude and hence it is a vector quantity.  The magnetic field shows the strength of a magnet and the direction of the force of the magnet. The strength of the magnet is represented by magnetic field lines from north to south and south to north inside and outside the magnet respectively.

Compass Needle:

A compass needle is a small magnet. A north pole is the end of the compass that points north, while a south pole is an end that means south. Magnets with like poles repel one another, while magnets with opposite poles attract each other. The compass needle is a small instrument which helps in finding the right direction of the magnetic field. The needle consists of a small metal needle and it directs in a different direction due to the magnetized needle. The needle aligns with the magnetic field of the Earth and points direction.

Magnetic field and Field lines:

The magnet affects the area in which it is located. As a result, the iron filings are subjected to a force. Iron filings are arranged in a pattern as a result of this force.

• A magnetic field occurs in the region around an interest in which the magnet’s force may be observed.
• Magnetic field lines are shown by the lines along which the iron filings position themselves. A field line is a path along which a hypothetical free north pole would migrate.
• The direction of the magnetic field is towards the compass needle when placed in the magnetic field. Here the north pole of the compass needle travels inside it, and the magnitude of the magnetic field is taken to be the magnitude of the magnetic field. 
• As a result, the field lines are assumed to originate from the north pole and combine at the south pole.

• The field lines inside the magnet run from the south pole to the north pole. Magnetic field lines are hence closed curves.
• The degree of closeness of the field lines indicates the relative intensity of the magnetic field.
• There are no field lines that intersect one another.

Magnetic field due to a current-carrying conductor:

• The magnetic field pattern created by an electric current passing through a conductor is determined by the conductor’s form. 
• The magnetic field produced by a current flowing through a straight conductor (wire) is proportional to its distance.
•  The field lines around the wire are concentric circles, with the right-hand rule determining their orientation. 
• The magnetic effects of electric current helps in detection of the magnetic field and its direction around the conductor with flow of current.

Fleming’s Right-Hand Thumb Rule and Left Hand Rule

• Imagine holding a current-carrying straight conductor in your right hand, with your thumb pointing in the direction of the current and your fingers wrapping around the conductor in the order of the magnetic field lines. 
• According to Fleming’s left hand rule, on stretching the thumb, forefinger, and middle finger of the left hand in a mutually perpendicular direction, the first finger points in magnetic field direction and second finger in direction of current. The thumb points in the direction of motion.                               

Magnetic Field due to a Current through a Circular Loop: 

The concentric rings depicting the magnetic field surrounding a current-carrying circular loop would get larger and larger as the distance from the wire increased. When the arcs of these large circles approach the circular loop’s center, they look like straight lines.

Magnetic Field due to a Current in a Solenoid:

• A solenoid is a coil made up of numerous circular turns of insulated copper wire tightly wound into a cylinder form. 
• The magnetic field of a current-carrying solenoid is comparable to that of a bar magnet. The solenoid’s one end acts as a magnetic north pole, while the other acts as a magnetic south pole. 
• When a piece of magnetic material, such as soft iron, is placed within the coil, a strong magnetic field created inside the solenoid may be utilized to magnetize it. An electromagnet is a magnet that has been produced in this way.

  Conclusion 

Magnetic effects of electric current help understand the force created by magnetic dipoles during the flow of electric charges. The direction of the magnetic field through a conductor during the flow of electric current is represented with the help of the Right Hand Thumb Model. The needle compass is a small instrument with a magnetic needle that helps show the direction of the magnetic field.