Electromagnetic waves are kind of radiation which are formed when eletric field couples with a magnetic field.
Magnetic and electric fields of electromagnetic wave are perpendicular to each other.
Unlike sound waves, electromagnetic waves donot need medium such as molecules to travel.
Electromagnetic waves are used while listening to radio, using microwave, etc.
In 1860s and 1870s, James Clerk Maxwell developed scientific theory and noticed that electrical fields and magnetic fields can be coupled together to form electromagnetic waves. This relationship between electricity and magnetism was summarized into “Maxwell’s Equations”.
Another scientist Heinrich Hertz applied Maxwell’s theories for the production and receiption of radio waves. (Hertz – unit of frequency of radio wave named to honour Heinrich Hertz)
Further, electromagnetic waves are different from mechanical wave which need medium to travel.
What is an Electromagnetic Wave?
Most waves we encounter like sound or water ripples are mechanical. They need matter (a “medium”) to travel, bumping molecules together like falling dominoes. But Electromagnetic (EM) waves are different. They don’t need a medium at all, which is why they can travel through the absolute vacuum of space.
The Anatomy: Coupled Fields
An EM wave is born when a charged particle (like an electron) moves, creating an electric field. As that field changes, it induces a magnetic field. These two fields are “coupled” together, vibrating at perfect 90-degree angles to one another.
The Electric Field (E): Vibrates vertically.
The Magnetic Field (M): Vibrates horizontally.
Propagation: Both fields travel together at the speed of light.
So, how are electromagnetic waves used?
The Physics of Invisible Data
Every time you send a text or stream a video, you're using a phenomenon that James Clerk Maxwell theorized and Heinrich Hertz proved: Electromagnetic Radiation.
1. Anatomy of the Wave
Unlike sound waves (which are mechanical and need air molecules to bump into each other like dominoes), electromagnetic waves don't need a medium. They can travel through the total vacuum of space.
The Physics: When charged particles like electrons move, they create an electric field. A changing electric field induces a magnetic field, and vice-versa. These two fields are "coupled" together, vibrating at perfect right angles (perpendicular) to each other as they zip through space at the speed of light.
■ Electric Field (E) ■ Magnetic Field (M)
2. How Data Rides the Wave
A raw EM wave is just a constant hum, it doesn't "say" anything. To transmit your photos or messages, we have to modulate it.
The Process: Think of the EM wave as a carrier. We take your digital data (the orange line) and force the wave to change its properties to match. In Frequency Modulation (FM), we keep the wave's height the same but bunch the waves together to represent a "1" and spread them out to represent a "0". This is how your phone "talks" to a cell tower miles away.
