Physics

Guglielmo Marconi sent out the first wireless signals. In the early summer of 1895 and despite an intervening hill, Marconi achieved signal transmission and reception over a distance of about 2km. Success was indicated initially by the waving of a handkerchief and progressed to the need to fire a gun. The theory of relativity transformed theoretical physics and astronomy during the 20th century. When first published, relativity superseded a 200-year-old theory of mechanics stated by Isaac Newton. In 1900 Max Planck made a profound discovery in modern physics / Quantum Theory. He showed (from purely formal / mathematical foundations) that light must be emitted and absorbed in discrete amounts if it was to correctly describe observed phenomena (i.e. Blackbody radiation). The Wright brothers, Orville (August 19, 1871 – January 30, 1948) and Wilbur (April 16, 1867 – May 30, 1912), were two American brothers, inventors, and aviation pioneers who were credited with inventing and building the world’s first successful airplane and making the first controlled, powered and sustained heavier-than-air human flight, on December 17, 1903.

Stationary wave is formed by two waves of same frequency travelling in the opposite direction.

The diesel engine gains its energy by burning fuel injected or sprayed into the compressed, hot air charge within the cylinder. The air must be heated to a temperature greater than the temperature at which the injected fuel can ignite.

Joule per kelvin is the unit of the physical quantity Entropy.