Table of Contents
Electromagnetic radiations have been made up of electromagnetic waves that are generated when an electric field collides with a magnetic field. Electromagnetic waves are often characterised as an oscillating combination of electric and magnetic fields. These waves solve Maxwell’s equations, which are the fundamental equations of electrodynamics. In overall, a charged particle generates an electric field. Other charged particles are influenced by this electric field. Positive charges accelerate in the direction of the field, while negative charges accelerate in the opposite direction. A moving charged particle generates the magnetic field. One such magnetic field exerts a force on other moving particles. Since the force acting on these charges is always perpendicular to their velocity, it only changes the direction of the velocity rather than the speed. Finally, an accelerating charged particle generates the electromagnetic field. Electromagnetic waves are nothing more than electric and magnetic fields travelling at the speed of light c through free space. Whenever a charged particle oscillates around an equilibrium position, it is said to be accelerating and if the charged particle’s frequency of oscillation is f, it produces an electromagnetic wave with frequency f.
This wave’s wavelength is given by λ= c/f. Electromagnetic waves are a kind of energy transfer that occurs in space. Electromagnetic waves are extremely important in our daily lives. Most people don’t think about it, but many of our daily activities would be impossible without electromagnetic waves. These activities include everything from listening to music in our cars to simply being able to see with our eyes. Electromagnetic waves are indeed a type of wave that, unlike sound and water waves, can travel through a vacuum without the use of a medium. When a particle vibrates, it emits energy in the form of electromagnetic radiation, which causes these waves to form. Such energy is made up of two parts: an electric component and a magnetic component. Such waves radiate outward from the source and oscillate perpendicular to the motion direction. The electric and magnetic fluctuations, on the other hand, occur in two different planes that are perpendicular to each other.
Electromagnetic (EM) waves may transport energy through space. One such radiation is associated with entangled electric and magnetic ﬁelds which must exist simultaneously. Even though all electromagnetic waves travel at the speed of light in a vacuum, 3×108 m/s, they cover a wide range of frequencies known as the electromagnetic spectrum. The different parts of the electromagnetic spectrum are given different names based on their different properties in the emission, transmission, and absorption of the corresponding waves, as well as their various practical applications. There have been no distinct boundaries separating these various portions, and the ranges frequently overlap. From lowest to highest frequency (longest to shortest wavelength), the EM spectrum contains the following waves: radio frequency (RF), microwaves, millimetre waves, terahertz, infrared, visible light, ultraviolet, X-rays, and gamma rays. Overall, the applications of EM waves are heavily influenced by their frequency (wavelength). Trying to harness the capabilities of electromagnetic waves has had a significant impact on a variety of fields, including wireless communication, industrial sensing/imaging, biomedical sensing/imaging and treatment, remote sensing, radar, security screening, wireless power transfer, and so on.
Applications of Electromagnetic Waves
(1) Television and radio use radio waves for communication.
Radio waves are easily transmitted through the air. They don’t really harm the human body is absorbed, and they can be reflected to change their direction. Because of these characteristics, they are ideal for communication.
Oscillations in electrical circuits can generate radio waves. When radio waves are absorbed by a conductor, an alternating current is produced. The frequency of this electrical current is the same as that of radio waves. A radio aerial, for example, could serve as the conductor.
Before transmission, information is encoded into the wave, which can then be decoded when the wave is received. This principle is used by television and radio systems to broadcast information.
(2) Microwaves can be used for both cooking and satellite communication.
Higher-frequency microwaves emit frequencies that are easily absorbed by food molecules. Whenever molecules absorb microwaves, their internal energy increases, resulting in heating. Microwaves travel easily through the atmosphere, allowing them to communicate between ground stations and satellites in orbit.
(3) Electrical heaters, cookers for cooking food, and infrared cameras that detect people in the dark use infrared light.
Some chemical bonds absorb the frequencies of infrared light. Whenever the bonds absorb infrared light, their internal energy increases, resulting in heating. So, infrared light is useful for electrical heaters and cooking food. Infrared light is emitted by all objects. Such light is invisible to the human eye, but infrared cameras can detect it. One such ‘thermal imaging technology can detect people in the dark.
(4) Visible light has been light that we can see.
And is used in fibre optic communications, where light pulses are coded and transmitted through glass fibres from a source to a receiver.
(5) Ultraviolet radiation could indeed kill bacteria found in water, sterilising it and making it safe to drink.
Ultraviolet radiation is however beneficial to the skin because it aids in the production of vitamin D. Too much UV exposure, on the other hand, can cause skin problems.
(6) Layered random medium models, which include anisotropic effects, discrete scatterers, random distribution of discrete scatterers, and rough surface effects, have been used to simulate snow-ice fields, forests, vegetation canopies, ploughed fields, sea ice, and the atmosphere is active and passive microwave remote sensing. The scattering and emission of electromagnetic waves by random media with rough interfaces are studied. The effects of multiple scattering of electromagnetic waves by a layer of densely distributed discrete scatterers are investigated. The modified radiative transfer equation, which accounts for multiple scattering effects, is derived using the strong fluctuation approach. Active remote sensing with dipole antennae and line sources has also been investigated for monochromatic and pulse excitations.
Electromagnetic waves are very important in everyday life. Ultraviolet, X-ray, and gamma-ray waves are at higher frequencies on the spectrum, while infrared, microwave and radio waves are at lower frequencies. Such waves are not visible to the naked eye, but we can detect them and use them to our advantage using modern devices. Many of the devices we use on a daily basis use radio waves. Radios, for example, receive radio waves and can then interpret them as sound. Our phones, too, use radio waves to send and receive signals. When examining our bones, doctors use X-rays to determine whether or not anything is broken. Microwaves are also used in our homes to heat food.
Q. How do EM waves apply in cookery and the physical world?
Ans: Microwaves, as well as infrared waves, can heat food, but they do not render it “radioactive.” These same waves cause the molecules in the food to vibrate vigorously, resulting in a high temperature that cooks the food.
Q. How would EM wave applications affect humans in their daily lives?
Ans: An exposure to strong enough low-frequency fields can cause dizziness, light flashes, and tingling or pain due to nerve stimulation. However, exposure to strong enough radiofrequency fields can cause heating of body tissue and damage to tissues and organs.
Q. Why are microwaves useful?
Ans: Since microwave energy can penetrate haze, light rain and snow, clouds, and smoke, it is ideal for transmitting information from one location to another. In remote sensing, shorter microwaves are used. Such microwaves are used for radar, such as doppler radar, which is used in weather forecasting.