81. In which decade were the first successful diode and triode vacuum tubes invented?
(a) 1800s (b) 1880s (c) 1890s (d) 1900s
Answer
Answer : (d)
Explanation
Explanation : In 1904, John Ambrose Fleming invented the first practical electron tube called the ‘Fleming Valve’, which is a diode rectifier. In 1906, Lee de Forest invented the audion later called the triode, which provided signal amplification. Let us discuss.
82. In which decade was the Internet first implemented?
(a) 1940s (b) 1950s (c) 1960s (d) 1980s
Answer
Answer : (c)
Explanation
Explanation : The first message ever sent over what is now called the Internet took place at 10:30PM on October 29, 1969. Back then, the Department of Defense called it ARPAnet (Advanced Research Projects Agency network). Let us discuss.
(a) Sir Frank Whittle (b) Gottlieb Daimler (c) Roger Bacon (d) Lewis E. Waterman
Answer
Answer : (a)
Explanation
Explanation : Dr. Hans von Ohain and Sir Frank Whittle are recognized as the co-inventors of the jet engine. Each was working separately and knew nothing of the others work. Although Whittle started first, von Ohain was first to design and develop a turbojet engine to power an aircraft. Of the many honors received by both, the most significant honor was probably “The Charles Draper Prize” in 1992 which was given to both Hans von Ohain and Sir Frank Whittle for their efforts and contributions to aviation and mankind. “The Charles Draper Prize” is recognized as the equivalent to the Nobel Prize in technology. Let us discuss.
5555555555112. In which decade was the telephone invented? (a) 1850s (b) 1860s (c) 1870s (d) 1880s