What are Electromagnetic Waves [EM Waves]?

By : Neha Dhyani

Updated : Jun 15, 2022, 6:55

Electricity and magnetism are two static forces. As we already know, a change in the magnetic field will automatically induce changes in the electric field or vice-versa. The two static forces are invariably linked. These changing fields form Electromagnetic Waves. From the 1860s to the 1870s, James Clerk Maxwell, a Scottish scientist, developed a theory to explain Electromagnetic Waves. He was the first to notice that electric and magnetic fields can produce these waves.

He summarized his findings and research into equations known as Maxwell's equations to explain the relationship between electricity and magnetism. Maxwell's equation plus Lorentz force formula gives us the mathematical expression for all electromagnetism laws.

Experimental Demonstration of Electromagnetic Waves

In 1887, Heinrich Hertz, a German physicist, experimentally proved the existence of Electromagnetic Waves. He produced radio waves, and his experiments proved that radio waves included all features of Electromagnetic Waves.

Hertz was named the unit of frequency after Heinrich Hertz to honour his outstanding contribution. His experimental demonstration with radio waves created ripples in the science society.

It proved the credibility of Maxwell's theories by -

1. Proving the speed of radio waves is equal to the speed of light.

2. Figuring out how to make magnetic and electric fields detach themselves from transmitting wires and travel freely as per Maxwell's prediction of Electromagnetic Waves.

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Electromagnetic Spectrum

It's a broad spectrum that includes all types of electromagnetic radiation. It is classified based on the frequency of em waves.

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Types of Electromagnetic Waves

There are essentially seven types of Electromagnetic Waves-

Radio waves - were created through an acceleration motion of charges in conducting wires. They are primarily used in commutation systems like cellular phones, TVs, and radios. Their frequency ranges from 500 kHz to 1000 MHz

Microwaves - They are short-wavelength radio waves and are produced via unique vacuum tubes. They are used for aircraft navigation.

Visible rays - The human eye detects this type of EM wave. Visible rays are a reflection of objects that reach human eyes.

Ultraviolet rays - Sun is the central source of ultraviolet rays. Long-term exposure to UB rays in large quantities can harm humans.

Infrared waves - are produced by hit molecules and are sometimes also called heat waves. It keeps the earth's temperature warm through the greenhouse effect.

X-rays - X-rays are popular due to their medical applications in the industry. It works as a diagnostic tool and is part of the treatment that kills cancer.

Gamma rays - They have considerably high-frequency radiation, which is produced during nuclear reactions. Radioactive nuclei emit energy.

An electric charge that oscillates harmonically with a frequency will produce Electromagnetic Waves of the same frequency. The discovery of EM Waves has significantly helped create innovations and make our lives easier.

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FAQs on Electromagnetic Waves

Q1. Give an example of a source of Electromagnetic Waves.

One example of the basic source of Electromagnetic Waves is the electric dipole.

Q2. What is the wavelength range of Gamma rays in Electromagnetic Waves?

With regards to Electromagnetic Waves, gamma rays have a frequency from 10m to less than 10-14m.

Q3. Name one applicability of infrared waves in the context of Electromagnetic Waves

Infrared waves are used to make infrared detectors present in Earth satellites, used for military and agriculture purposes. This is one of the most important uses of this kind of electromagnetic wave.

Q4. What's the difference between mechanical and Electromagnetic Waves?

Electromagnetic Waves can travel through solid materials, air, and the vacuum of space. In comparison, mechanical waves need a medium to propagate.