An electromagnet is an object that acts like a magnet. Electricity creates and controls the magnetic force, thus the name electromagnet. Electromagnetism works when electricity passes through a wire and creates a magnetic field around the wire. Looping the wire further increases the magnetic field. A solenoid is an electromagnetic created without an iron core. Various factors determine the strength of an electromagnetic field. These are; the amount of current, the number of coils of wire, and the distance from the wire. The unit that measures magnetic force is Tesla. The strength of the magnetic fields is equally proportional to the current in the wire. That is Voltage= Current * Resistance (V=I*R). The magnetic force is proportional to the number of turns around the coil. The strength of an electromagnetic is inversely proportional to the length of air gap between the poles.
An electromagnetic is stronger than a permanent magnet since it produces stronger magnetic fields and one can control its strength by varying the number turns in its coil or changing the current flowing though the coil. One can also switch on and off an electromagnet. Lastly, reversing the current can reverse the poles of the magnetic field.
Electromagnetism is widely used in industries, hospital equipment and is essential in our everyday lives.
Electromagnetism works when electricity passes through a wire and creates a magnetic field around the wire. Magnetic and electric fields are very vital concepts found on earth. The interrelations between these two concepts results in electric currents, which have a wide application. Today, electromagnetism is widely used in our day-to-day lives.
One of the major applications of electromagnetism is the speakers. A speaker contains a cone, voice coil, and a permanent magnet. The terminals of the voice coil connect to the back of the panel receiver. The panel receiver then sends signals through the voice coil, which interact with the magnetic field of the magnet. The magnet changes the forces within it by pushing and pulling the cone. This pushing and pulling of the cone results in sound waves.
The electric generator also uses the concept of electromagnetism. In an electric generator, current rotates in the magnetic field. The action of falling waters causes this rotation, as the waters hit the turbine blades making them rotate. This results in the generation of an alternating magnetic field through the plane of the wire loops. The mechanical energy present in the turbines converts to electric energy. As the loop rotates, there is generation of current, which is the AC current produced.
A transformer also uses electromagnetism in its functioning. A transformer is an electric device that converts Ac power at a voltage level to Ac power at a different voltage level but under the same frequency.
Electromagnetism is also applied in the field of medicine. Living organism use electromagnetic waves in body processes. In medicine, it is believed that there is a wide range of electric fields present within organisms. There are also a number of magnetic fields, electromagnetic waves, and weak photons emitted by the body cells, organisms, and tissues. An understanding of the role of electric fields assists individuals to obtain information that affects living systems in beneficial ways.
A cyclotron is a device that accelerates charged particles to high energies. It works on the principle that a charged particle moving normally to a magnetic field experiences Lorentz magnetic forces, which the particle moves in a circular path. When a positive charge emits from the source, it accelerates towards the dee with a negative charge at that moment. The ion experiences normal magnetic charge forces and rotates. When the ion gets to the path between the dees, the polarity reverses. The particle is thus accelerated and moves into the dee with greater velocity along a circle of greater radius. As the particle moves in a spiral path, the radius increases. The particle moves to the edge. The particle with high energy hits the target. A cyclotron accelerates protons, deuterons, and alpha particles.
Electromagnetic applications use electromagnetic interactions in their operations. Electronic magnetic fields describe Electromagnetic interactions. This is best expressed in Maxwell’s equations. Maxwell’s equations are a set of differential equations that relate the electric and magnetic fields to their sources, charge density, and current density. These equations also describe how a time varying electric field generates a time varying magnetic field and vice versa. To express Maxwell’s equation we need to understand Gauss law and Gauss law for magnetism. These laws describe the source of magnetic fields. Magnetic fields originate from charges. They also describe the way in which the magnetic fields rotate their origins. Magnetic fields revolve around electric currents and time varying electric fields. This is Amperes law. Faraday’s law states that the electric fields revolve around time varying magnetic fields.
Gauss law describes interrelation between an electric field and the generating electric charges. The electric field always points towards the negative charges and away from the positive charges. Electric field lines within a magnetic field begin from the point with positive electric charges and terminate where there are negative electric charges.
Gauss law of electricity states that the number of electric field lines passing through a Gaussian surface is directly proportional t the total charge enclosed by the Gaussian surface. This is the first of Maxwell’s equations. This is to say that, any magnetic field line getting into a given volume must exit that volume. A Gaussian surface is a closed surface and closing a given volume. Gauss law is equivalent to coulombs law in terms of making observations on the field lines, which coulombs law geometrically represents.
Faradays law states that a change in the magnetic field induces an electric field. Faradays law of magnetic induction states that the charge induced in a circuit is proportional to the time rate of change of the magnetic flux linking a closed wire circuit.
Ampere’s law states that generation of magnetic fields takes place in two ways. It occurs by either electric current or by changing the electric fields. Any alterations made on the magnetic field create an electric field. An alteration on the electric field generates a magnetic field. Therefore, electromagnetic waves travel in empty space.
Where E represents electric field, B represents the magnetic field, D represents the electric displacement field, and H represents the magnetizing field.
This is Maxwell’s first equation. It represents covering of the entire surface with large tiny patches having the area . The areas are small that they cannot be flat. The vector magnitude dA is the area value with a perpendicular direction. With the electric current, the dot product selects the field components that are pointing outwards. The second Maxwell equation is the analogous magnetic field.
In this case, the flow of the magnetic flux into a surface is equal to the flow outside the surface. The net flux in an enclosed volume is always zero. These two equations represent the flow of electric and magnetic fields over closed surfaces. Let us look at the flow of current around closed curves. This is Maxwell’s third equation.
The path for electrostatics. We describe this equation using Faraday’s Law of induction. If a closed circuit has alternating magnetic flux flowing through it, this gives rise to a circulating current. This shows that the voltage around the circuit is nonzero. The complete equation is. The integrated right hand side uses the circuit on the left side. There is no clear definition of the right hand side in determination of the nature of the surface. When we put two surfaces both having wires as a boundary together, the final surface is a single closed surface. A closed surface is and implies that for either of the surfaces surrounded is equal to or the other surface. When we put the two surfaces together, the result is a zero. We should note that integrals for closed surfaces have area vectors pointing outwards. The two surfaces are always equal. The vector points in a different direction in terms of volume to the other vector. The end surface integral is which the same for any surface directing the path. From Maxwell’s third equation, Ampere’s law, Magnetic currents counted thread though the integrated path. We need to determine the direction of flow and pay less attention to currents flowing in the opposite direction.
Maxwell used a long wire carrying steady current as an example to demonstrate Ampere’s law. The wire breaks at some point and put in circular plates and a capacitor. The flow of current remains steady such that charge piles on one plate and the other plate drains off. Applying Ampere’s law, the magnetic field at distance r from is using the right hand rule. With Maxwell’s parallel plates capacitor, if one wants to distort the surface, current runs between the plates. In this case, we have to rescue Ampere’s law. Since current is not flowing across the surface, putting current between the capacitors changes the electric field as the capacitor charges up as current flows through it. In a case where the plates are next to each other, we take the electric field lines from the charge q on one plate so that it flows to the next one. The total electric flux across the surface between the plates is the current in the wire is the rate charges changes ion the plate the two equations together are we can write Ampere’s law correctly as this is Maxwell’s fourth equation. This means that, the current in the wire, or the increasing electric field are on the right hand side depending on the position of the wire.
It is essential to write Maxwell’s equations in other forms within which their representations will still be Maxwell’s equations. In special relativism, we use covariant field tensors though quantum mechanics is more preferable.