Radio Waves- Discovery, Bands, Uses, Practice Problems, FAQs

How do we watch our favourite show on television while sitting in the comfort of our own homes? The evolution of radio wave-based communication technology is exclusively responsible for this. Television, AM and FM broadcasting, mobile phones, military communications, and other communication technologies all use radio waves. As a result, communication technology has become an indispensable part of our everyday life. Let's look at radio waves, which help in signal transmission through multiple channels.

Table of Contents

• Radio Waves
• Discovery of Radio Waves
• Radio Wave Bands
• Uses of Radio Waves 
• Practice Problems
• FAQs

Radio Waves

The longest wavelength waves in the electromagnetic spectrum are radio waves. These waves are a kind of electromagnetic radiation with a frequency ranging from 300 GHz to 3 kHz, however they are referred to as microwaves if their frequency exceeds 3 GHz. The wavelength at 300 GHz is 1 mm, but at 3 kHz it is 100 km. They, like all other electromagnetic waves, move at the speed of light. Lightning or celestial objects are responsible for all naturally produced waves. Radio communication, radar, computer networks, broadcasting, various navigation systems, and other uses all employ artificially produced radio waves. Radio waves are formed when charged particles accelerate.

If we arrange the electromagnetic spectrum in order of increasing wavelengths, radio waves will be near the end of the spectrum, as seen below.

Discovery of Radio Waves

James Maxwell, who utilised Maxwell's equation to predict the behaviour of electromagnetic waves, was the first to predict the existence of radio waves. Heinrich Hertz was the first to show the concept. On the other hand, Guglielmo Marconi was responsible for the first successful practical use, for which he received the Nobel Prize. For the first time, radio waves, first known as Hertzian waves and subsequently renamed Radio waves, were used commercially in 1900.

Radio waves are classified into two types. Great waves may go around obstacles and propagate over long distances, such as mountains, as well as follow the planet's curves. Because the ground is not a perfect conductor, the signal is cancelled as it follows the earth's surface. The Earth's ionosphere reflects the shorter waves, which travel in a straight line with a range of observable horizons. Long waves are referred to as ground waves, whereas short waves are referred to as sky waves.

In some way, everything in space emits radio waves. The sun emits radio waves on a regular basis, which may be detected by space-based radio telescopes. These aid us in anticipating a solar flare that might disrupt our communication system.

Radio Wave Bands

According to the range of frequencies radio waves are divided into different bands as shown in the table below. 

Band	Frequency Range	Wavelength Range
ELF (Extreme Low Frequency)
VLF (Very Low Frequency)
LF (Low Frequency)
MF (Medium Frequency)
HF (High Frequency)
VHF (Very High Frequency)
UHF (Ultra High Frequency)
SHF (Super High Frequency)
EHF (Extreme High Frequency)

Spectrum of radio wave bands is shown in the diagram below:

Uses of Radio Waves 

Radio waves are employed in all of our communications around the world, from the mobile network to vintage radio stations, from television to military communications.

• One of the most popular uses of radio waves is radio broadcasting. The signal is modulated using various modulation methods. The modulated signal is subsequently encoded and disseminated over the airwaves through radio transmitters. On the receiving end, the signal may be retrieved by simply tuning the receiver to the same frequency as the transmitter.
• Radio waves may readily pass through solid things and obstacles such as houses and trees. As a result, the smartphone's internal circuitry includes a radio transmitter and radio receiver, allowing for the transmission and reception of signals through radio waves.
• RADAR (Radio Detection and Ranging) uses radio waves to detect the presence and position of an item.
• Radio astronomy makes use of radio waves to provide a more detailed view of planets, comets, asteroids, and other celestial objects.
• The bulk of remote-controlled devices employ radio waves. As a result, the user may operate the device from afar.

Practice Problems

Q 1. Explain the use of radio waves in MRI?
A. Radio waves are commonly employed in the medical industry. Radio waves, for example, are employed in magnetic resonance imaging (MRI) machines to offer a detailed and crisp 3-dimensional image of the patient's internal organs. Because radio waves have no harmful side effects, they are useful for MRI scans and other medical treatments.

Q 2. How does the Air Traffic Controller (ATC) make use of radio waves?
A. One of the most common uses of radio waves is to establish a secure communication network between planes and the air traffic control unit. VHF (extremely high frequency) radio waves are widely used for this purpose. Radio waves are also used to maintain air-to-air contact between the planes.

Q 3. Explain the working of RADAR?
A. Radio waves are used in RADAR (radio detection and ranging) to identify the presence and location of an object. The RADAR's transmitting antenna transmits radio waves into the surroundings. These waves are transported through the air and bounce back when they hit an object. The radio receiver then collects the reflected waves. The speed with which the wave travels and the time taken by the wave to return is noted. As a result, the position of the object can be calculated. 

Q 4. What is the application of radio waves in satellite communication?
A. With the help of satellites, radio waves are utilised to transmit information over enormous distances. The earth's radio wave antennas are used to transfer signals to the satellite. The received signal is then sent back to the ground station by the satellite. The information is taken from this signal after it has been processed. One of the most effective uses of radio waves in satellite communication is television transmission.

FAQs

Q 1. What types of signals do mobile phones use?
A. Radiofrequency (RF) or non-ionizing radiation is used by mobile phones and other wireless devices. This allows us to transmit and receive voice text messages, photographs, and access the internet.

Q 2. What makes radio waves different from radioactive waves?
A. Radio waves are a form of electromagnetic wave that is employed in a variety of applications, most notably in human communication. These waves are non-ionizing and are thought to be the safest for animals and plants. Radioactive waves, on the other hand, are ionising waves that are released by radioactive materials. Gamma rays are the most frequent radioactive waves. These waves are frequently dangerous to living things.

Q 3. What is the use of radio waves in submarines?
A. Submarine communication systems make use of radio waves to facilitate the flow of information. Extremely low-frequency (ELF) radio waves are commonly used for this. This is due to the fact that these rays are not easily absorbed by the ocean.

Q 4. Which electromagnetic radiation has the longest wavelength?
A. Radio waves has the longest wavelength of range .