THE MIRACLE OF RADIO

SUMMARY:

 Wireless is the greatest discoveries of the age. It has revolutionized the methods of communications. The names of three persons, Maxwell of England, Hertz of Germany and Marconi of Italy, stand out from among those who have made it possible.

James Clerk Maxwell, who was born in 1831, put forward the theory that light and electricity are parts of the same thing. The theory was based on mathematical calculations. It was later observed that light waves and electric waves moved at the same speed which comes to about 186,000 miles per second. Wireless waves are yet to be discovered to as the connecting link between electric waves and light waves.

Heinrich Hertz, a German, made laboratory tests with short frequency electric waves to prove that Maxwell’s theory was correct. These waves were named Hertzian waves after him, and they established the possibility of wireless communication. In 1894 Lodge showed that it was practicable.

Guglielmo Marconi, the son of an Italian father and an Irish mother, saw his teacher making this demonstration, and was observed with the idea. He experimented with a Morse Telegraph key and a telephone receiver and received the signal from one to the other without any wire. The standing aerial doubled the strength of the wireless waves.

In 1896 Marconi went to England and presented his invention to the British Government. In 1897 the Marconi wireless Telegraph Company was founded there. The Postal Department, the Navy and the Press gradually became interested in this invention.

In 1907 Marconi successfully transmitted wireless signal over long distances and showed that the earth’s curve did not interfere with these waves. After that ships began to use these for distress signals.

In 1912 Marconi managed to direct wireless in a straight line. This invention opened up new vistas. After that it was made sound rather than sound signal. This led to the invention of radio, or the broadcasting system for entertainment and instruction.

Another scientist Baird invented the method of sending pictures by radio. That was the brining of television, which was invented before the Second World War but became popular after it. This transmission is in black and white but colour television, which is very costly, has also been invented.

Another development of wireless waves is the radar. It has made air traffic safe by making it possible to locate aircraft. Radar works on the principal that flying aeroplane’s high frequency waves can be detected. This detection helps to avoid collisions.

One of the latest developments is the radio telescope. The invention is based on the discovery that stars emit wireless waves. The radio telescope has made the exploration of universe possible.

Questions and Answers:

Q.1 At what speed do wireless waves move? What other waves move at this speed?

Ans. Wireless waves move at the same speed as light waves. This speed comes to about 186000 miles per second.

Q.2 Why were wireless waves once called Hertzian waves?

Ans. Wireless waves were once called Hertzian waves because German scientist Heinrich Hertz had been the first person to discover them.

Q.3 In what years were wireless signals first transmitted over the English Channel at the Atlantic Ocean? Who was responsible for these successful experiments?

Ans. Wireless signals were first transmitted over the English Channel in 1896 and cross the Atlantic Ocean in 1901. Marconi was responsible for both of these successful experiments.

Q.4 What facts are given in the text about the first use of wireless to bring help to a ship in distress?

Ans. When the liner Republic collided with another ship in the Atlantic, wireless signals were for the first time used to seek help in her distress.

Q.5 Could speech be transmitted in early days of wireless signalling?

Ans. No, speech could not be transmitted in the early days of wireless signalling. The Morse Code was used instead of communication by this means.

Q.6 During what period did sound broadcasting become generally established?

Ans. Sound broadcasting became generally established in 1920’s.

Q.7 In what way is television an advance upon sound broadcasting?

Ans. Television is an advance upon sound broadcasting since pictures and not just speech sound can be sent by it.

Q.8 Is television in colour possible? If so, why is not in general use?

Ans. Television in colour has been made possible. But it is not in general use because it is much more expensive than the ordinary radio transmission of black and white pictures.

Q.9 What is the function of radar?

Ans. The function of the radar is to locate the position of aircraft and ships.

Q.10 What use can the astronomer now make of radio?

Ans. The astronomer can now explore the vast universe. This has been made possible by the use of the radio telescope. It works by detecting radio waves sent by distant stars.