Historical Dates and Firsts

Max Planck introduced quantum theory in 1900 to explain blackbody radiation, proposing that energy is emitted in discrete packets called 'quanta'. This revolutionary idea founded quantum mechanics, though Planck himself was initially skeptical of its implications.

Silicon was first isolated in its pure form by Swedish chemist Jöns Jacob Berzelius in 1824. He accomplished this by heating potassium fluorosilicate with potassium metal, producing amorphous silicon.

Einstein published his special theory of relativity in 1905, during his 'annus mirabilis' (miracle year) when he published four groundbreaking papers. The theory fundamentally changed our understanding of space, time, and energy.

Uranus was discovered by William Herschel in 1781 using a telescope he built himself. Herschel initially thought he had found a comet, but further calculations showed it was a new planet - the first discovered since ancient times.

X-rays were discovered by Wilhelm Conrad Röntgen in 1895 while experimenting with cathode ray tubes. He noticed a fluorescent effect on a nearby screen and realized an unknown radiation was responsible, calling them 'X-rays' due to their mysterious nature.

CT scanning (CAT scan) was developed by Godfrey Hounsfield and Allan Cormack around 1972-1973, with the first clinical CT scan performed in 1971. The technology revolutionized medical imaging by combining X-rays with computer processing to create cross-sectional images.

Oxygen was discovered by Carl Wilhelm Scheele in 1772, though Joseph Priestley independently discovered it in 1774 and published first. Antoine Lavoisier later named it 'oxygen' and recognized its role in combustion.

The safety razor was invented by King Camp Gillette in 1895, featuring a disposable blade design that made shaving safer and more convenient. This invention led to the founding of the Gillette Company and revolutionized personal grooming.

The safety elevator was invented by Elisha Graves Otis in 1852-1853, with the first demonstration in 1853. The 1861 date likely refers to Otis's patent or a significant installation. Otis's safety mechanism prevented elevators from falling if cables broke, making tall buildings practical.

Uranium was discovered by German chemist Martin Heinrich Klaproth in 1789. He named it after the planet Uranus, which had been discovered eight years earlier in 1781 by William Herschel.

This is the correct option. The first World Cup was held in 1975.

The third generation of computers (1965-1971) was characterized by the use of integrated circuits (ICs) instead of individual transistors. This generation saw the development of smaller, more reliable, and more powerful computers. The first generation used vacuum tubes (1940s-1950s), the second used transistors (1958-1964), and the fourth generation used microprocessors (1971-present).

Walmart was founded by Sam Walton in 1962 in Rogers, Arkansas. The company grew from a single discount store to become the world's largest retailer, revolutionizing retail through its low-price strategy and supply chain innovation.

1683 is given as the correct answer for the discovery of bacteria. Antony van Leeuwenhoek first observed bacteria in the 1670s using microscopes, with 1683 being a commonly cited year for his bacterial observations. 1867 is too late, 1955 and 1939 are much too recent.

Christiaan Eijkman discovered that beriberi was caused by a deficiency in the diet, specifically lack of thiamine (vitamin B1), through his work with polished rice in 1897. This was a crucial discovery in understanding nutritional diseases.