Those waves which have a frequency range of few kilo hertz to few hundred mega hertz are known as radio waves. The most common frequencies which are used by the radio waves are discussed below: 1. HF: - HF means high frequency band. Its frequency range is between ...

The major function of the ozone layer is to stop the harmful radiations coming from the sun as well as from stars. Ozone captures those radiations which are of low wavelength. It also stops the harmful ultraviolet rays. These radiations are very harmful for living ...

The atmosphere shows variation in behavior for different types of radiations. The sun and the stars present in our atmosphere are clearly visible to us. This is due to the visible radiations. These radiations change the behavior of the atmosphere to transparent. But our atmosphere has ...

The envelope made up of gases which is surrounding our earth is known as atmosphere. There are lot of gases which combine together to form the atmosphere. The major composition of atmosphere is shown below in the table: Gases Composition Oxygen 21% Nitrogen 78% Carbon-dioxide .03% Other(argon, hydrocarbons, water vapors, dust particles, ...

The receiving, sending and processing of information using space as a medium is called space communication. The information is sent in the form of sound waves. To send the information, electromagnetic wave is used as a carrier. The electromagnetic wave is of very high frequency. ...

FAX is basically a technique of reproducing a document electronically at a distant place. FAX machine is an example of digital communication system. Uses of a fax machine: (a) It sends all the data over the telephone lines. Even the images are converted into digitized form ...

As we know that the computers can’t understand our language. Computers understand the language of 0’s and 1’s i.e. digital form. The modem will modulate the signal into a sine wave. So, this modulated digital signal can easily run over the telephone lines. ...

Modem is a device which is used to connect two computers with the help of ordinary telephone lines. Voltage changes are not tolerated by our ordinary telephone lines. This limitation is overcome by using a modem. 1. It transforms the digital signals into audio signals for ...