Radio Wave

The German physicist, Heinrich Hertz, first applied the theory given by Maxwell to prove the existence of radio waves in 1887. Television and radio networks transmit a signal using radio waves. The introduction of radio and television has had a profound impact on many aspects of society and culture, particularly on the humanities.

Radio allowed for the transmission of music all around the world, bringing different styles like opera and bluegrass to parts of the world that had never even imagined such things.

These radio waves are produced by electrons moving backwards and forwards in a transmitting aerial.

Radio waves have the longest wavelengths of all the types of electromagnetic radiation.

Radio wavelengths range from about a centimeter to many kilometers.

Radio waves can travel large distances through the air or empty space. They make electrons in the antenna of your television or radio vibrate and this can be converted into the sounds or images you see and hear when turning in.

The prime purpose of radio is to convey information from one place to another through the intervening media (i.e., air, space, nonconducting materials) without wires.

Besides being used for transmitting sound and television signals, radio is used for the transmission of data in coded form.

Also the radio waves are the waves having the longest wavelength in the electromagnetic spectrum. It has a frequency from as high as 300 GHz to as low as 3 kHz. One way to make Radio waves visible is with something like a radio telescope.

An ordinary (light) telescope collects light and focuses it onto a receptor (CCD, photographic plate, the eye), thus making it possible to see the visible radiation emitted by a distant galaxy.

Different wavelengths of radio waves have different properties an dare used for different purposes. The main types of electromagnetic waves used in communication are:

Microwaves(wavelength around 3 cm)

Short radio waves (wavelength around 30 cm)

Long radio waves (wavelength in the range 3-3000m).

Microwaves are useful for 'line-of-sight' Communications where the transmitter can point directly at the receiver. Since microwaves can pass straight through Earth's atmosphere, they can also be used for transmissions between Earth and Communication satellites. space satellite.

In comparison, short-wave radio signals can be transmitted long distances around the globe. This is because they are reflected by the ionosphere, which is a layer of the atmosphere 75-100 km above Earth's surface. short-wave radio signals are beamed upwards at an angle, they can bounce back and forth between Earth ionosphere to be detected tar away from where the transmitter is located. audio signal Similarly, long radio waves are used for communications because they bend around the Earths surface when transmitted.

Radio Waves are also produced naturally. Objects in space, such as stars. emit radio waves. Because microwaves can pass straight through Earth's atmosphere, they can also be used for transmission between Earth and communication satellites.

AM and FM Radio:

Each radio station broadcasts its signals using a carrier wave which has a frequency that is specific to that Station. Typically AM signals are transmitted at lower frequencies than FM signals. AM and FM signals also use different methods to encode the music being transmitted.

AM stands for Amplitude Modulation which means the audio signal is used to change (or modulate) the amplitude of the carrier wave. In an FM (Frequency Modulation) system, the audio signal is used to change the frequency of the carrier wave. When you tune your radio receiver to a particular station. you set it to detect the frequency of the carrier wave. Complex circuitry inside your receiver subtracts the carrier wave from the modulated radio waves, leaving only the original audio signal. The full process of radio transmission is summarised.

Sample Questions

(More Questions for each concept available in Login)

Question : 1

Who discovered the radio waves?
A. The AMERICAN physicist, Heinrich Hertz		B. The German physicist, Heinrich Hertz
C. Both A and B		D. None of these
Right Option : B
View Explanation

Question : 2

The meaning of AM and FM is _____________________.
A. FM (Fast Modulation), AM (Amplitude Modulation)		B. FM (Frequency Modulation), AM (Amplitude Modulation)
C. FM (Frequency Modulation), AM (Angular Modulation)		D. None of these
Right Option : B
View Explanation

Question : 3

The frequency of radio waves is?
A. as high as 30 GHz to as low as 3 kHz		B. as high as 300 GHz to as low as 3 kHz
C. as high as 300 GHz to as low as 30 kHz		D. None of these
Right Option : B
View Explanation