CHAPTER # NO 05
(THE MIIRACLE OF RADIO)
(ALL QUESTIONS / ANSWERS SINDH BOARD)
Q1: At what speed to wireless waves move, which other waves move at the speed at this speed Ans: The wireless waves move at the same speed as that of light waves, the speed of the wireless waves as about 1, 86,000 miles/sec.
Q2: Why were wireless waves once called Hertzian waves?
Ans: The wireless waves were called Hertzian waves in the honour of a German scientist Heinrich Hertz who discovered and demonstrated the secrets of the wireless waves and these waves made possibility of the wireless communication.
Q3: In what years, were the wireless signals first transmitted over the English Channel and the Atlantic Ocean, who was responsible for these successful experiments? Ans: Wireless signals were first transmitted over the English Channel in 1899 it was used by British Naval Maneuver. Wireless signals crossed the Atlantic Ocean in 1901. It was an excellent triumph of Guglielmo Marconi, a brilliant Italian Scientist. He had done both these experiments successfully.
Q4: What facts are given in the text about the first use of wireless to bring help to a ship in distress?Ans: In 1903, a ship used the wireless for the first time to send signals when the liner Republic collided with another ship in the Atlantic Ocean. It was a fine record of life saving at the sea by sending message through wireless signals.
Q5: Could speech be transmitted in the early days of wireless signaling? If not, how were messages transmitted?
Ans: Speeches could not be transmitted in the early days of the wireless signaling. Messages were sent through the slower and most awkward method of Morse code of dots and dashes.
Q6: During which period did the sound broadcasting become generally established?
Ans: In 1924, Marconi carried out his invention one step forward. He arranged the method of directing the wireless waves in a straight line, it advanced towards the transmission and reception of the wireless waves carrying sound waves. Sound broadcasting was
Ans: The television is advance upon sound broadcasting because it carries the sound and the picture; in nineteen thirties a brilliant scientist Baired devised a method of sending pictures by the radio.
Q8: Is television in colour possible? If So, why is it not in General use ?
Ans: In early days the regular service transmitted pictures in black and white. Television in colour has been made possible since long only the huge expenses of colour television have prevented its general use. It is more expensive then the ordinary radio transmission of the black and white pictures.
Q9: What is the fun the function of the radar?
Ans: The radar is the device that can locate the position of ship or an aeroplane to within a particular distance, it works on the principal that high frequency waves of the flying aeroplanes can be detected The ship equipped with the radar can avoid the collision in fog and darkness, position and movement of the other ships can be observed through the radars, the aircraft is directed through the radar with the help of radar an aircraft can land safely in the darkness and bad weather without the risk of collision.
Q10: What use car What use can the astronomer now make of radio?
Ans: It has been discovered that stars emit radio waves. Now it is possible to catch these waves by the use of radio telescope. Radio telescope with the huge aerials and sensitive receivers catch radio waves from stars and galaxy. It has assisted the astronomers to explore the mystery of this universe.
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