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Introduction:
In 1820, HC Oersted proved that electric current creates a magnetic field around it. Michael Faraday observed this and believed that if an electric current can create a magnetic field, then a magnetic field can also create a current. In 1831, Faraday showed the world that if a magnet is moved inside a copper coil, a very small electric current is induced in it.
This gave a new direction in the research of magnetism and forces related to it. So, in this article, we will have a detailed discussion about the Magnetic Field and its characteristics, force on a current-carrying conductor, and magnetic field due to a current-carrying wire.
Body:
Magnetic Field
The magnetic field can be defined as a measure of the magnetic force that can be observed by interacting particles in a certain space. The magnetic field can arrange the magnetic objects in the direction of the field. For example, Earth’s Magnetic field makes a magnetic needle compass, and other magnetic objects line up in the direction of the field.
Force due to magnetic field
The motion of the charges is always responsible for causing a magnetic field or magnetic force on magnetic objects. It is often stated that the two charges that have the same amount of charge and are moving in similar directions develop an attractive magnetic force between them. At the same time, the two charges that move in opposite directions develop repulsive magnetic force between them.
Explanation: If we consider two charged and moving objects, they will have some amount of magnetic force developed between them. However, the direction of the force will always depend on the charge that each of the objects possesses. One of the easy ways to find the magnetic force that develops between the two charges is by assuming that a constant amount of charge, q, is moving with some constant velocity, v. The magnetic field, in this case, is assumed to be B. The relation between velocity and magnetic fields is that they always work perpendicularly. Here is how we write the formula of the magnetic force due to a magnetic field imposed on a charged particle:
Fm = qv×B.
Where q is the charge, B is the magnetic field, v is the velocity and θ is angle between magnetic field and velocity. Remember, they always form a cross product and act perpendicular to each other. Here, the velocity and magnetic field form a cross product that can be represented by:
Fm = qvBsinθ.
To find the direction of the magnetic field, we always use Fleming’s right-hand thumb rule. As per the rule, the fingers of the right hand are stretched in such a form that the thumb, centre finger, and forefinger are in perpendicular directions to each other. In such stretching, the direction of the forefinger points to the direction of the magnetic field if the thumb points in the direction of the conductor’s motion and the centre finger points in the direction of the induced current.
Magnetic Field Lines
The direction of the magnetic field at a point can be determined with the help of a magnetic needle. If a magnetic needle is brought near a magnet, the magnetic needle will rest in a specific direction. However, if the position of the magnet is changed, the needle will also move in a curved path. This proves that the magnetic field line takes the form of a curve.
These curved lines that govern the movement of the magnetic needle are called magnetic field lines or lines of force. These magnetic field lines take the form of a closed curve.
The direction of the North Pole determines the direction of magnetic field lines.
Properties of magnetic field lines of force
- Magnetic force lines always originate from the magnet’s north pole, making a curve and entering the south pole. They pass through the magnet’s south pole and again come back to the north pole, forming a circle around the magnet.
- Two magnetic lines of force can never intersect because that would mean there are two directions, which is not possible.
- Where the magnetic field is strong, the lines of the curve are close. When it is weak, the lines of the curve are further apart.
- The lines of force of a uniform magnetic field are parallel and at equal distances.
- Lines of force in a magnetic field are imaginary lines that show the surface direction of the magnetic field in that place.
- A tangent drawn at any point on the magnetic force lines shows the magnetic field’s direction at that point.
Solenoids
A solenoid is an arrangement formed by wrapping a copper wire on a glass or cardboard tube in a spiral form. A solenoid can act as a powerful rod magnet when a current is passed through it.
The greater the number of turns of the conductor wires on the solenoid, the greater the power of the magnet. The north pole and south pole of a solenoid magnet are formed according to the direction of the current.
Properties of the magnetic field lines inside the solenoid:
The strong magnetic field produced by a solenoid results in magnetic field lines. The magnetic field lines in the solenoid resemble parallel straight lines.
The magnetic field is the same at all points inside a solenoid, which means a uniform magnetic field inside the solenoid. This magnetic property of the solenoid is used.
Conclusion:
Magnetic fields are an essential factor in understanding many aspects of life on earth, including the navigation of ships and the movement of climate systems across the earth’s surface. To understand natural phenomena better, magnetic field lines offer a very usual visualisation method that allows scientists to determine the effects of the earth’s magnetic field on day-to-day human life and natural phenomena on the planet.
The study of magnetic fields is an exciting area of research in physics. Exciting developments will continue in the study of magnetics for decades to come. For example, findings using pulsed-field magnets that operate at high altitudes, equipped with tools that take full advantage of electronics development, could take research in the field into thrilling new directions.
