Here we have explain the topic on the magneticeffect of current or magnetic effect due to current. When an electric current flows through a conductor, it produces a magnetic field around it. Obviously, this phenomenon is the magnetic effect of electric current.
What is a magnetic field?
Actually, a magnetic field is the region where a piece of magnetic material or another magnet experiences force. We can not visualize a filed around a magnet. A magnet always creates a magnetic field around it. Also, a electric current produces a magnetic field around its path.
We represent a magnetic field imagine some curved lines. We refer these lines as magnetic field lines. Actually, when we place a free to move unit magnetic north pole in a field, it experiences a force. This force makes the unit north pole to move. This movement happens in a specific path. The visual representation of this path is a magnetic field line.
Suppose, we place a unit north pole at the north pole of a magnet. Due to repulsive force between the same type of pole, the unit north pole will go away from the north pole of the magnet. at the same time, the unit north pole will go towards to the south pole of the magnet. At every point of its travel, it experiences both repulsive and attractive force on it simultaneously due to north and south poles of the magnet respectively.
As a result, the resultant force continuously change its direction at every point of the travel of the unit pole. This changing direction of the resultant force on the unit pole makes the shape of the magnetic line typically curved.
Properties of Magnetic Field Lines
Therefore, we can say that the magnetic lines go from North pole to South pole outside the magnet. They are continuous lines and form closed loops. They are closer where the magnetic field is strong but never intersect each other.
Magnetic Field Due to Current in a Straight Conductor
Suppose a current flows in a straight wire. Also, it create the magnetic field. This field creates concentric circular closed magnetic lines around the wire. Also, the concenter of the field lines lies on the central axis of the wire. There is nothing like segregated north pole or south pole in a straight conductor. Although, here the Right-Hand Thumb Rule determines the direction of the field lines .
Right-Hand Thumb Rule
If you hold the current-carrying conductor in your right hand with the thumb pointing in the direction of current, then the curled fingers show the direction of magnetic field lines.
Magnetic Field Due to a Circular Loop
A circular wire carrying current produces a magnetic field similar to that of a bar magnet. At the center of the loop, the lines are almost straight and parallel. If we the number of turns increases the magnetic field. Although, here lines of the magnetic field of current follows the same right hand rule but in reverse way. In contrast, here, the thumb indicates the direction of the magnetic field. Whereas, the the curled fingers show the direction of current.
Magnetic Field Due to a Solenoid
A solenoid is a long, insulated coil of many turns. The coil produces a uniform magnetic field inside it when current flows through the turns. The field pattern looks like that of a bar magnet. Obviously, one end of the solenoid acts as a North pole depending on the direction of current in the turns. The other end acts as a South pole depending on the same reason. The magnetic field lines inside the coil run in straight lines parallel to each other. The magnetic lines are also closed to each other inside the coil than that at outside of the coil. So, the magnetic field inside the coil is stronger than the outside and uniform.
Electromagnet
We we insert a soft iron core inside a current-carrying solenoid it becomes an electromagnet. When we insert an iron core, the magnetic field becomes much stronger. The iron is a magnetic material made of tiny magnetic domains. In normal conditions, these domains point in random directions. But now, the magnetic field of the solenoid forces these domains to align in the same direction. As the domains align, the iron core itself becomes an electromagnet. Because of this, the total magnetic field inside the solenoid equals the magnetic field of the solenoid plus the magnetic field of the iron core. This combination greatly increases the magnetic strength.
We use electromagnet in electric bells, electrical protection relays, motors, MRI machines, cranes for lifting scrap iron.
