Production, Characteristics, and Nature of Electromagnetic Waves: In our daily lives, we use gadgets like radios, mobile phones, Bluetooth, WiFi, and TV remote, which transfer data without any wires. We have also observed the formation of a rainbow. In the health sector, technologies like X-ray, CT-scan, Chemotherapy have revolutionized the health care sector and have made diagnosis much easier.

The harmful ultraviolet ray from the sun which can cause many skin diseases including cancer. The harmful radiation from nuclear power plants or radioactive elements can cause mutations in humans and other living beings. All these phenomena are due to electromagnetic waves. It is interesting to note that all are electromagnetic waves, from harmless radio waves to lethal gamma rays. Let us discuss in detail all these different electromagnetic waves in the given article.

Waves

Waves are a disturbance in space that propagate from one place to another, transferring energy and momentum. Waves can be categorized based on several parameters, but the most significant is based on the requirement of the medium.

Based on the requirement of the medium, waves can be categorised into the following two categories.

1. Mechanical Waves: Mechanical waves are a type of waves that do require a medium to propagate. The medium should be elastic and must possess inertia. for example, sound waves

2. Electromagnetic Waves: Electromagnetic waves are the type of waves that do not require a medium to propagate. For example, light waves, X-rays, gamma rays

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Electromagnetic Waves

Electromagnetic waves are waves that do not require a medium to propagate from one place to another. These waves propagate in space through the oscillating electric field and magnetic field. The direction of oscillation of the electric and magnetic fields are perpendicular to each other. These waves are distinguished or categorised based on their frequency and the corresponding wavelength.

Electromagnetic Spectrum

When different electromagnetic waves are arranged in order of their frequency or wavelength, the given representation is known as the electromagnetic spectrum. It can either be increasing or decreasing order.

Important Terms

1. Wavelength: The distance the disturbance travels in one complete vibration by a medium particle is known as the wavelength \((\lambda)\). The wavelength can also be defined as the distance between two successive crests or troughs in a transverse wave. In a longitudinal wave, the wavelength \((\lambda)\) is equal to the distance from the centre of one compression (or rarefaction) to the centre of the next compression (or rarefaction).

2. Amplitude: The amplitude of a wave is the maximum displacement of the medium particles from their mean position.

3. Frequency: The number of vibrations made by a particle of the medium in one second is called the frequency of the wave. It is represented by. Its unit is hertz \((\mathrm{Hz}), \mathrm{v}=\frac{1}{T}\)

4. Time-Period: The time taken by a particle to complete one complete vibration is called the time period of the wave.
\(T=\frac{1}{v}\), it is expressed in seconds.

5. Wave Velocity: Wave velocity is the velocity of propagation of the wave in the given medium. It is different from particle velocity. Wave velocity depends upon the nature of the medium. (Particle velocity keeps on changing as it oscillates with a fixed mean position)
Wave velocity \((v)=\) frequency \((v) \times\) wavelength \((\lambda)\)

Gamma Rays

Gamma waves are the most energetic waves in the electromagnetic spectrum. These waves have the highest frequency and the shortest wavelength. These waves are highly dangerous for living beings, and they can even be used to kill cancer cells, tumors, bacteria, and viruses. The energy possessed by a wave is directly proportional to the frequency of the wave.

Production

Gamma rays are produced in radioactive decays and nuclear reactions. In outer space, the gamma rays are produced by the nuclear reaction in the sun and the stars

Characteristics

Gamma waves’ wavelength range is from \(0.01 \,A^{0}\) to \(0.1 \,A^{0}\) and the frequency range from \(3 \times 10^{22} \mathrm{~Hz}\) to \(3 \times 10^{19} \mathrm{~Hz}\). The waves can transfer energy to the electrons of a photoelectric substance. These waves have a very high penetrating power

Application

Gamma rays are used in chemotherapy to kill cancer cells. It is used to detect any defect in metal castings. It is used to sterilise and disinfect medical instruments. It is also used in nuclear power plants.

X-rays

X-rays are a type of highly energetic electromagnetic wave that lies between ultraviolet rays and gamma rays. It possesses greater energy than ultraviolet rays but less energy than gamma rays. 

Production

X-rays are produced When an energised electron collides with a middle surface due to this collision. The electron in the metal gets energised and releases some energy in the form of an electromagnetic wave to go back to a stable state. This radiation corresponds to the X-ray in the electromagnetic spectrum.

Characteristics

X-rays wavelength ranges \(0.01\) to \(10\) nanometres, corresponding to the frequency range \(10^{16}\) to \(10^{20}\) Hertz. Different elements have a different characteristic frequency of the X-ray associated with it. Henry Moseley explained this.

\(f=2.48 \times 10^{15}(Z-1)^{2} \,\text {Hz}\)

Where,

\(Z\) is the atomic number of the element

Applications

(i) In the diagnosis of bones.

(ii) CT scan uses x-rays to determine the amount of damage that has occurred in internal organs.

(iii) In the security checks at metros and airports. X-rays can reveal what is inside of the baggage, and they can detect metals and explosives or any suspicious objects present inside the baggage. So, authorities can be alarmed for manual checks, and required actions can be taken.

(iv) In industries: X-rays can be used to detect the quality of industrial products or in construction. X-rays can be used to determine any deformity or an air gap.

Ultraviolet Waves

These waves are less energetic than Gamma waves and X-rays, but they are still fatal for living beings. Long exposure to these waves can cause various diseases, including cancer.

Production

Ultraviolet rays are produced by the sun. The ozone layer of the atmosphere absorbs the Ultraviolet radiation from the sun and protects us.

Characteristics

Ultraviolet waves have a wavelength range from \(100 \,A^{0}\) to \(4000 A^{0}\) And the frequency range is from \(5 \times 10^{17} \mathrm{~Hz}\) to \(8 \times 10^{14} \mathrm{~Hz}\). Ultraviolet rays can also show the photoelectric effect

Applications

Ultraviolet rays are used the sterilise water in some water purifiers, and it is also used in purifying the air in hospitals.

It is used to determine the authenticity of cheques and currency notes.

Visible Spectrum

These waves lie in between the Ultraviolet and infrared waves in the electromagnetic spectrum. These are not harmful to humans or living beings. The white light that comes from the sun is itself not visible, but when it incidents on any surface and gets reflected by it, we perceive that reflected wave to have the sensation of the vision.

Production

Visible light comes from the sun and the stars. Bulbs and LEDs can also produce it.

Characteristics

For the visible waves in the electromagnetic spectrum, the wavelength ranges from \(4000 \,A^{0}\) to \(8000 \,A^{0_{A}}\) nd the frequency is \(8 \times 10^{14} \mathrm{~Hz}\) to \(4 \times 10^{14} \mathrm{~Hz}\).

The superposition of the seven colours obtains white light, that is, Violet, Indigo, Blue, Green, Yellow, Orange, 

Applications

Visible light is responsible for our vision.

Infrared Waves

These waves lie between visible and micro-waves in the electromagnetic spectrum. They can transfer heat. It is one of the modes of the transfer of heat. The heat from the sun gets transferred to the earth via infrared radiation. These waves are also known as heatwaves.

Production

Infrared radiations are produced by all bodies that are radiating heat.

Characteristics

Infrared waves’ wavelength ranges from \(8000 \,A^{0}\) to \(4000\,{\rm{\mu m}},\) frequency ranging from \(4 \times 10^{14} \mathrm{~Hz}\) to \(10^{11} \mathrm{~Hz}\).

Applications

Infrared radiation detectors are used in night vision.

Micro-waves

Micro-waves are the wave that lies in between the radio-waves and infrared wave in the electromagnetic spectrum of the electromagnetic wave.

Production

Microwaves are produced inside the microwave ovens. It is used to heat food material. Microwaves have frequencies close to the natural frequency of the water molecule and transferring the energy into them, thereby increasing the temperature of the food.

Characteristics

Microwaves’ wavelength ranges from \(4000\,{\rm{\mu m}}\) to \(10^{-2} \,\mathrm{~m}\) and a frequency range from \(10^{11} \mathrm{~Hz}\) to \(10^{9} \mathrm{~Hz}\).

Applications

Used to the heat food material.

Microwaves can be used for communication purposes.

Microwaves can be used as radar.

Radio Waves

Radio waves have the longest wavelength and the lowest frequency. These waves can travel large distances.

Production

Radio waves can be produced by L-C oscillators.

The L-C oscillation produces an oscillating electric and magnetic field, whose frequency lies in the radio waves region of the electromagnetic spectrum.

Characteristics

Radio waves’ frequency lies between \(30 \,\mathrm{~Hz}\) to \(300 \,\mathrm{GHz}\), and the wavelength can range from thousands of meters to \(30 \,\mathrm{~cm}\).

Following are some important bandwidths for radio waves that are widely used.

1. The frequency range from \(530 \,\mathrm{kHz}\) to \(1710 \,\mathrm{kHz}\) is for an amplitude-modulated band.
2. The frequency range from \(1710 \,\mathrm{kHz}\) to \(54 \,\mathrm{MHz}\) is for a short wave band.
3. The frequency range from \(54 \,\mathrm{MHz}\) to \(890 \,\mathrm{MHz}\) is for television waves.
4. The frequency range from \(88 \,\mathrm{MHz}\) to \(108 \,\mathrm{MHz}\) is for frequency modulated band, used in commercial FM radio.

Applications

Following are some important bandwidths for radio waves that are widely used.

1. The frequency range from \(530 \,\mathrm{kHz}\) to \(1710 \,\mathrm{kHz}\) is for an amplitude-modulated band.
2. The frequency range from \(1710 \,\mathrm{kHz}\) to \(54 \,\mathrm{MHz}\) is for a short wave band.
3. The frequency range from \(54 \,\mathrm{MHz}\) to \(890 \,\mathrm{MHz}\) is for television waves.
4. The frequency range from \(88 \,\mathrm{MHz}\) to \(108 \,\mathrm{MHz}\) is for frequency modulated band, used in commercial FM radio.

Summary

Electromagnetic waves are oscillating electric and magnetic fields. Different types of electromagnetic waves have different wavelengths and frequencies but have a common velocity of propagation equal to the velocity of light. These electromagnetic waves are responsible for vision, heat transfer from the sun to the earth. These waves do not require a medium to propagate and thus can go from one place to another, even in space.
Different electromagnetic waves are employed in various fields like health, defence, security, communication, etc.

Learn About Sources of Electromagnetic Waves

FAQs

Q.1. Do all the waves in the electromagnetic spectrum travel at the same speed?
Ans: Yes, all the waves in the electromagnetic spectrum travel at the same speed equal to the velocity of light.

Q.2. Can we see the light?
Ans: The white light is itself not visible, but when it strikes an object, it gets reflected, and our eyes perceive the reflected rays to give us the sensation of the vision.

Q.3. Which is the wave that has the highest frequency?
Ans: Gamma waves in the electromagnetic spectrum have the highest frequency.

Q.4. Which is the wave that has the longest wavelength?
Ans: Radio waves are the waves that have the longest wavelength.

Q.5. Which is the wave that has the highest velocity?
Ans: All the waves in the electromagnetic spectrum have the same velocity that is equal to the velocity of light \(c=3 \times 10^{9} \mathrm{~ms}^{-1}\)

We hope this detailed article on the production, characteristics, and nature of electromagnetic waves helped you in your studies. If you have any doubts, queries or suggestions regarding this article, feel to ask us in the comment section and we will be more than happy to assist you. Happy learning!