Electromagnetic force

Electromagnetic forces

Introduction

Electromagnetic force is a special force that afects everything in the universe because it has an infinite-range attractive, like gravity; it is also a repulsive force which acts between charged particles. There are 4 fundamental forces in the universe; gravity, electromagnetism, strong nuclear force, and weak nuclear force. To start off, gravity is an attractive force between all matter, operates along all size scales but it dominates at the very large scale. Electromagnetism runs the same way, it operates along all size scales but it dominates at our scale; the human scale. So we essentially do live in an electromagnetic world. The particle that is used by electromagnetic forces are photons which have a strength of 1/137, a mass of 0 and a spin of 1 To look at electromagnetic forces, we can look at the charges. If we have a positive and a negative electric charge, it will result in attraction. If the electrical charges are the same, it will result in repulsion between the two. Another component of electromagnetic force is magnetic forces, if we have two magnetic dipoles, there is going to be attraction between the north and the south. The larger the magnet, the greater that force is going to be. Although magnets are different from electrical charges in that they don’t exist as a discrete north and south, there are still connections between electric charges and magnets. A charge can be generated if magnets are moved, and a magnetic field can be generated if a charge is moved, so essentially they are both the same thing. They also operate along all scales; however they dominate at the human scale. Electromagnetism is really one force; we can take charges as a proof. If we run charges (current) through a wire, and wrap it around a metal, which is not normally magnetic, it will generate a magnetic field and we’ve created something called an electromagnet. So a moving charge can create a magnetic field. We can take this electromagnet and spin it in a generator and we will generate current. A way to look at on how we can quantify those charges is Coulomb's law. So if we have two positive charges, there will be repulsion. If we have two opposite charges, there will be an attractive force. We can use Coulomb’s constant 9.0x109 N.(m/C)2 to figure out how great that force is going to be. So the bigger the charge the greater the repulsion or attraction is going to be (and the same applies to a magnet).

Medical importances

Radiation therapy is the treatment using penetrating x-rays, or particles such as protons or neutrons on the affected region of the body to destroy the cancer cells. Particle accelerators such as Cobalt-60 radiation therapy unit or clinic 2100 accelerator are used. Radiation therapy is a modern technique of treatment where the results are faster with fewer side effects than the more traditional techniques. There are different types of treatments like external beam radiotherapy, proton therapy, x-rays, and gamma rays. This type of therapy is used in radiation and oncology. This use of electromagnetism is still used nowadays.

MRI scanning uses magnetism, radio waves, and a computer to produce images of body structures. Scanning is painless and does not involve x-ray radiation. It uses protons which are abundant in the human body. All protons spin creating a small magnetic charge, when a small magnetic field is introduced, as is the case in an MRI machine, the proton aligns with that field. The MRI technician then introduces a radio frequency pulse that disrupts the protons and forces it into a different alignment direction. Since the radio frequency fields push the proton against its nature, once this pulse is turned off, the protons realign with the magnetic field releasing electromagnetic energy along the way. The MRI is able to detect this energy and is able to differentiate the different tissues based on how quickly they release energy after the pulse is turned off. This use of electromagnetism is still used nowadays.

Cathod ray tube (oscilloscopes)

Aside from these three examples, there are other various uses of electromagnetic forces: Mass spectrometry, Nuclear Magnetic Resonance (NMR), Cyclotrons.

Advantages and disadvantages

Electromagnetism is used in energy production (electromagnetic energy), and as always energy production has its advantages and disadvantages.

Advantages Electromagnetic energy is clean. It is not polluting like oil and coal energy sources, nor do we have to destroy the environment to get the raw materials--electrons are everywhere. It has no radioactive components that can explode violently or produce dangerous radioactivity for thousands of years. It also is renewable; we will never run out of electrons or magnetism. Besides being clean and renewable, electricity is versatile. We already know hundreds of ways to use electricity to cool, heat and drive motors of all sizes to perform all kinds of work. Electricity can be made to work on extremely small scales, such as in microchips. For packing a lot of information-processing power into a low energy-consuming package there is no other power source that even comes close.

Disadvantages The wireless transmission of electrical power is an idea that goes back to at least the early part of the 20th century. Nikola Tesla worked on the project and discovered the chief disadvantage: It is not easy to achieve. This challenge remains the major disadvantage. Even if it was easy, there is another disadvantage that worries many people: is it safe. Most researchers have concluded that Radio Frequency (RF) waves - the proposed means of transmission - are completely safe and that RF has no effect on living tissue. Not everybody agrees.