The three most commonly used Boolean operators are: AND, OR, and NOT. On the Web, Boolean operators are used in advanced searches to combine search items. For example, an "AND" operator between two words ("football AND television") tells the search engine to find documents that contain both of these words.
5. In which decade was the Internet first implemented?
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).
6. In which decade were the first successful diode and triode vacuum tubes invented?
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.