Inventions — Set 4

Correct Answer: D. Charles Kao

• **Charles Kao** = Charles Kao (known as the 'Father of Fiber Optics') calculated in 1966 that if glass fibre could be purified to reduce attenuation below 20 dB/km, it could carry light signals over long distances for communications. • **1966** — Kao's theoretical work led directly to the development of low-loss optical fibre; he shared the 2009 Nobel Prize in Physics for 'groundbreaking achievements concerning the transmission of light in fibres for optical communication.' • 💡 Wrong-option analysis: Jack Kilby: invented the integrated circuit (microchip) in 1958; Narinder Singh Kapany: pioneered early fibre optic research and coined the term 'fibre optics' but Kao solved the key transmission-loss problem; Robert Noyce: co-invented the integrated circuit independently of Kilby.

Correct Answer: D. Bifocal Lenses

• **Bifocal Lenses** = Benjamin Franklin invented bifocal spectacles around 1784 by cutting two different lenses in half and combining them in one frame — the upper half for distance vision and the lower half for reading. • **1784** — Before bifocals, people with both near- and far-sightedness had to carry two pairs of glasses and switch between them; Franklin's invention solved this with a single pair. • 💡 Wrong-option analysis: The Magnifying Glass: a simple convex lens used for enlarging objects, not invented by Franklin; The Telescope: invented by Hans Lippershey in 1608; Contact Lenses: first practical contact lenses were developed in the late 19th and 20th centuries, long after Franklin.

Correct Answer: A. Rudolf Diesel

• **Rudolf Diesel** = Rudolf Diesel patented the compression-ignition engine in 1892; instead of using a spark plug, it ignites fuel by heating air to high temperature through extreme compression (compression ratio ~14–22:1). • **1892** — Diesel's engine achieved about 26% thermal efficiency, nearly double that of contemporary steam engines; it is now used in ships, trucks, trains, and generators worldwide. • 💡 Wrong-option analysis: Gottlieb Daimler: developed high-speed petrol engines and built early motorcycles and automobiles; Karl Benz: built the first true petrol-powered automobile in 1885; Wilhelm Maybach: collaborated with Daimler on high-speed petrol engine design.

Correct Answer: B. Yi Xing

• **Yi Xing** = Yi Xing, a Chinese Buddhist monk and mathematician, built an astronomical water-driven mechanical clock with an escapement mechanism around 725 AD, considered the first true mechanical clock. • **725 AD** — Yi Xing's clock used a water-wheel escapement to regulate motion; this was the first device to use the escapement principle — the key mechanism in all subsequent mechanical clocks. • 💡 Wrong-option analysis: Peter Henlein: made the first portable spring-driven pocket watch around 1510 in Germany; Galileo Galilei: discovered the isochronous property of pendulums but did not build a clock; Christian Huygens: invented the pendulum clock in 1656, greatly improving accuracy.

Correct Answer: B. Bell Labs

• **Bell Labs** = John Bardeen, Walter Brattain, and William Shockley invented the point-contact transistor at Bell Laboratories on December 23, 1947, creating the first semiconductor device that could amplify and switch electronic signals. • **1947** — All three inventors shared the 1956 Nobel Prize in Physics; transistors replaced bulky, fragile, power-hungry vacuum tubes and made miniaturisation of electronics possible, leading directly to integrated circuits and modern computers. • 💡 Wrong-option analysis: NASA: a space agency founded in 1958, well after the transistor was invented; Intel Corporation: founded in 1968 to manufacture integrated circuits based on transistor technology; IBM Labs: conducts computing research but did not invent the transistor.

Correct Answer: B. Charles Fritts

• **Charles Fritts** = Charles Fritts built the first solid-state solar cell in 1883 by coating selenium with a thin layer of gold; when exposed to light, it produced a small but measurable electric current through the photovoltaic effect. • **1883** — Fritts's selenium cell had less than 1% efficiency; modern silicon solar cells (developed at Bell Labs by Pearson, Fuller, and Chapin in 1954) reach 15–20% efficiency, but Fritts demonstrated the principle first. • 💡 Wrong-option analysis: Gerald Pearson: co-invented the practical silicon solar cell at Bell Labs in 1954; Calvin Fuller: also co-inventor of the 1954 Bell Labs silicon solar cell; Albert Einstein: explained the photoelectric effect theoretically in 1905 (Nobel Prize 1921) but did not build a solar cell.

Correct Answer: D. Louis-Sebastien Lenormand

• **Louis-Sebastien Lenormand** = Louis-Sebastien Lenormand made the first recorded successful parachute jump on December 26, 1783 in Montpellier, France, leaping from a tall tree using a wooden-framed parachute about 4.6 m in diameter. • **1783** — Lenormand coined the word 'parachute' from Greek 'para' (against) and French 'chute' (fall); André Garnerin later made the first jump from a balloon in 1797. • 💡 Wrong-option analysis: Leonardo da Vinci: sketched a pyramid-shaped parachute design around 1485 but never built or tested it; Jean-Pierre Blanchard: a pioneering balloonist who made early parachute drops with animals; Andre-Jacques Garnerin: made the first jump from a high-altitude balloon in 1797 but jumped 14 years after Lenormand.

Correct Answer: C. Otto von Guericke

• **Otto von Guericke** = Otto von Guericke invented the first vacuum pump in 1650, using it to evacuate air from containers and demonstrate the enormous force of atmospheric pressure in the famous Magdeburg hemispheres experiment. • **1654** — In the 1654 Magdeburg demonstration, two teams of 8 horses each could not pull apart two evacuated bronze hemispheres, proving the immense pressure of the atmosphere. • 💡 Wrong-option analysis: Blaise Pascal: studied fluid pressure and verified atmospheric pressure experiments but did not invent the vacuum pump; Robert Boyle: used vacuum pumps (improved from Guericke's design) to formulate Boyle's Law but did not invent the first one; Evangelista Torricelli: invented the barometer in 1643 and created a limited vacuum above the mercury column.

Correct Answer: C. Hans Lippershey

• **Hans Lippershey** = Hans Lippershey applied for the first patent for a refracting telescope in October 1608, describing a device using two lenses in a tube that made distant objects appear three times closer. • **1608** — Although the Dutch government did not grant the patent (as others also claimed the invention), Lippershey's application is the earliest documented evidence of a working telescope; Galileo heard of it and built his own improved version in 1609. • 💡 Wrong-option analysis: Jacob Metius: filed a similar patent claim weeks after Lippershey but was denied; Zacharias Janssen: credited with the first compound microscope around 1590, not the telescope; Christiaan Huygens: made important improvements to telescope design and discovered Saturn's rings in 1655.

Correct Answer: B. John Deere

• **John Deere** = John Deere invented the self-scouring steel plough in 1837, whose highly polished steel surface allowed it to cut through the thick, sticky clay soil of the American prairie without clogging, unlike cast iron ploughs. • **1837** — Before Deere's steel plough, farmers had to stop every few metres to scrape soil off the iron plough; his invention enabled rapid agricultural expansion across the US Midwest. • 💡 Wrong-option analysis: Robert Fulton: built the first commercially successful steamboat; Cyrus McCormick: invented the mechanical reaper (grain harvester) in 1831; Eli Whitney: invented the cotton gin in 1793 and pioneered interchangeable parts manufacturing.