Inventions and Inventors: Pairs, Years and Exam PYQs

The correct answer is C, X-Rays. Roentgen, a German physicist, noticed in 1895 that a screen in his darkened laboratory glowed while a covered discharge tube was running, and he named the unknown radiation X-rays. For this he received the first Nobel Prize in Physics in 1901. Option A is wrong because the conservation of electric charge is a principle established through the work of Benjamin Franklin and others, not a discovery of Roentgen. Option B is wrong because a practical incandescent electric bulb was made by Thomas Alva Edison in 1879, sixteen years before the X-ray. Option D is wrong because thermodynamics grew out of the work of Carnot, Joule, Clausius and Kelvin and is a body of laws rather than a single discovery. Remember the pairing of Roentgen, X-rays, 1895 and the first physics Nobel of 1901 together.

The correct answer is C, Edward Jenner. In 1796 Jenner showed that material from a cowpox sore protected a boy against smallpox, the first deliberate vaccination, and the word vaccine itself comes from vacca, the Latin for cow. That experiment founded the science of immunology. Option A is wrong because Robert Koch identified the bacteria that cause tuberculosis and cholera and gave the rules for linking a microbe to a disease, so he belongs to bacteriology. Option B is wrong because Louis Pasteur gave the germ theory of disease, pasteurisation and the rabies vaccine, and is called the father of microbiology, although his vaccine work came after Jenner. Option D is wrong because Karl Landsteiner discovered the human blood groups. The trap in this question is Pasteur, whose fame in vaccines makes candidates skip the earlier name.

The correct answer is D, Vitamin D - Paul Muller, because this is the pair that does not match. Paul Hermann Muller is remembered for showing that DDT kills insects, work for which he received a Nobel Prize in Physiology or Medicine; vitamin D is associated with Edward Mellanby, who linked its absence to rickets, and with Adolf Windaus, who worked out its chemistry. Option A is correctly matched because Elmer McCollum identified the fat soluble factor that came to be called vitamin A. Option B is correctly matched because McCollum also identified the water soluble factor named vitamin B. Option C is correctly matched because Albert Szent-Gyorgyi isolated the substance later named vitamin C and won a Nobel Prize for that work. Read the word NOT in the stem carefully, since three of the four pairs here are deliberately correct.

The correct answer is B, Alexander Graham Bell. Bell received the patent for the telephone in 1876 and made the first call over a wire, carrying the human voice itself rather than a code. Option A is wrong because Samuel Morse built the electric telegraph in 1837 and gave the dot and dash code that bears his name, which sent messages but not speech. Option C is wrong because Guglielmo Marconi developed practical wireless telegraphy in the 1890s and sent signals across the Atlantic in 1901, again as code and without wires. Option D is wrong because Thomas Alva Edison, though he improved the telephone transmitter, is remembered for the practical electric bulb and the phonograph. The examiner keeps Morse and Marconi in the options precisely because all three men worked on sending messages over a distance.

The correct answer is A, Alfred Nobel. The Swedish chemist Alfred Nobel patented dynamite in 1867, a safe way of handling nitroglycerine, and the fortune he made from explosives endowed the Nobel Prizes, first awarded in 1901. Option B is wrong because Rudolf Diesel invented the compression ignition engine that carries his name, not an explosive. Option C is wrong because Michael Faraday discovered electromagnetic induction and built the first dynamo, a machine that generates electricity; the similarity between the words dynamite and dynamo is exactly the trap the paper setter is laying. Option D is wrong because James Watt improved the steam engine, and the unit of power is named after him. Keep the chain in mind: Nobel, dynamite, 1867, and the prizes that began in 1901 on the anniversary of his death, 10 December.

The correct answer is B, Alexander Fleming. Fleming noticed in 1928 that a mould of the genus Penicillium had killed the bacteria growing around it on a culture plate, and the substance he named penicillin became the first antibiotic; Florey and Chain later turned it into a usable drug and shared the Nobel Prize with him. Option A is wrong because Joseph Lister introduced antiseptic surgery using carbolic acid, which prevents infection during an operation rather than curing one. Option C is wrong because Jonas Salk developed the injectable polio vaccine in the 1950s, a vaccine and not an antibiotic. Option D is wrong because Robert Koch identified disease causing bacteria but did not find a drug against them. A vaccine prevents a disease and an antibiotic kills bacteria already in the body, and papers test that distinction.

The correct answer is C, James Chadwick. Chadwick showed in 1932 that the radiation given off when beryllium is struck by alpha particles consists of neutral particles of about the mass of a proton, and he named them neutrons; he received the Nobel Prize in Physics for it. Option A is wrong because J. J. Thomson discovered the electron in 1897 through his cathode ray experiments. Option B is wrong because Ernest Rutherford discovered the atomic nucleus with the gold foil experiment and named the proton, and although he had predicted a neutral particle, he did not find it. Option D is wrong because Niels Bohr gave the model of the atom in which electrons occupy fixed energy levels. Fix the order for the exam: electron in 1897, nucleus and proton with Rutherford, neutron with Chadwick in 1932.

The correct answer is A, Tim Berners-Lee. Working at the CERN laboratory in 1989, Berners-Lee proposed a system of linked documents and wrote the first web browser and server, giving the world HTML, HTTP and the address form known as the URL. Option B is wrong because Ray Tomlinson is credited with electronic mail in its modern form and with the use of the at sign to separate the user from the host. Option C is wrong because Charles Babbage designed the difference engine and the analytical engine in the nineteenth century and is called the father of the computer, long before any network existed. Option D is wrong because Vint Cerf, with Bob Kahn, designed the TCP and IP protocols that carry data across the internet. The internet is the network itself; the web is one service running on it, and papers test that difference.

The correct answer is B, Charles Babbage. Babbage designed the difference engine and then the analytical engine, a mechanical machine with a store, a mill and punched card input, which carried every idea of a modern general purpose computer, and he is therefore called the father of the computer. Option A is wrong because Alan Turing gave the theoretical model of computation known as the Turing machine and worked on codebreaking, a century later. Option C is wrong because John von Neumann described the stored program architecture that most computers still follow, but that came in the 1940s. Option D is wrong because Blaise Pascal built a mechanical adding machine, the Pascaline, in 1642, which could add and subtract but could not be programmed. Remember also that Ada Lovelace, who wrote an algorithm for the analytical engine, is called the first programmer.

The correct answer is A, Evangelista Torricelli. In 1643 the Italian scientist Torricelli filled a long glass tube with mercury and inverted it in a dish, and the column that stayed up showed that the air outside was pressing on the mercury; that apparatus is the mercury barometer, and the unit torr is named after him. Option B is wrong because Anders Celsius gave the centigrade temperature scale, which belongs to the thermometer and not the barometer. Option C is wrong because Robert Boyle stated the law relating the pressure and volume of a gas, a law about pressure but not an instrument to measure it. Option D is wrong because Blaise Pascal, though he carried a barometer up a mountain to prove that pressure falls with height and has the unit of pressure named after him, did not invent the instrument. A falling barometer reading warns of a storm, which is why the instrument matters in weather questions.