Science & Technology Mixed Quiz: Set 12

The correct answer is C, about 1.1 eV. The energy gap between the valence band and the conduction band decides whether a solid conducts: in silicon the gap is roughly 1.1 electron volts, small enough for heat or light to lift some electrons across it, which is what makes silicon a semiconductor. Option A is wrong because 0.3 volt is the forward barrier voltage of a germanium diode, a different quantity altogether. Option B is wrong because about 0.7 eV is the band gap of germanium, the other elemental semiconductor, and it is also the forward voltage drop of a silicon diode, which is why candidates confuse the two numbers. Option D is wrong because about 5.5 eV is the gap in diamond, an insulator. Learn the trio together: germanium 0.7 eV, silicon 1.1 eV, gallium arsenide about 1.43 eV.

The correct answer is C, August 2021. The Prime Minister announced the National Hydrogen Mission in his Independence Day speech from the Red Fort on 15 August 2021, with the aim of making India a hub for producing and exporting green hydrogen. Green hydrogen is made by splitting water through electrolysis using electricity from solar, wind or other renewable sources, so it releases no carbon dioxide, unlike the grey hydrogen made from natural gas. The Union Cabinet later approved the National Green Hydrogen Mission in January 2023 with an outlay of Rs 19,744 crore. Option A is wrong because May 2021 saw no such announcement. Option B is wrong because November 2021 is when the Prime Minister gave the Panchamrit climate pledges at the Glasgow COP26 summit. Option D is wrong because January 2021 belongs to the vaccination drive against Covid-19, not to hydrogen. Exam tip: announced 15 August 2021; the mission was approved by the Cabinet in January 2023.

The correct answer is B, John McCarthy. He coined the phrase artificial intelligence in the proposal for a summer research workshop held at Dartmouth College in 1956, and that conference is treated as the moment the subject was founded; McCarthy also created the LISP programming language and is commonly called the father of artificial intelligence. Option A is wrong because Alan Turing, though he asked whether machines can think and gave the Turing Test in 1950, never used the phrase itself; the field was named six years after his paper. Option C is wrong because Marvin Minsky, a major figure who attended the same Dartmouth meeting and later founded the MIT AI laboratory, did not coin the term. Option D is wrong because Joseph Weizenbaum is remembered for ELIZA, the first conversational program, written in the mid-1960s.

The correct answer is C, protozoa. Malaria is caused by the protozoan Plasmodium and carried by the female Anopheles mosquito, and kala azar, also called visceral leishmaniasis, is caused by the protozoan Leishmania donovani and carried by the sandfly. Both are handled by the national centre for vector borne diseases, which is why they appear together in papers. Option A is wrong because the bacterial group holds typhoid, tuberculosis, cholera and plague. Option B is wrong; fungal infections are of the skin, hair and nails and none of them is spread by a mosquito or a sandfly. Option D is wrong although it is the commonest error, since dengue, chikungunya and Japanese encephalitis are indeed viral and are also spread by insects, so candidates assume every insect borne disease is a virus. Fix malaria and kala azar firmly on the protozoan side.

The correct answer is B, Germany. LHB stands for Linke Hofmann Busch, the German firm whose design Indian Railways adopted at the end of the 1990s and now builds at Kapurthala and other coach factories. These coaches are made largely of stainless steel, are lighter than the older ICF coaches, ride more smoothly at high speed, and carry anti-climbing features and a centre buffer coupler so that in a collision the coaches do not ride over one another, which is the reason they are considered safer. Option A, Japan, supplies the Shinkansen technology for the high-speed corridor, not the coach design. Option C, South Korea, and option D, Russia, have supplied equipment to India in other sectors but not this coach design. Note the pattern examiners like: German coaches, Japanese bullet train and Indian train sets from Chennai.

The correct answer is D, 1.6 W/kg. The Specific Absorption Rate measures how much radio energy from a handset the body takes in, in watts per kilogram of tissue. From 1 September 2012 the Department of Telecommunications made 1.6 W/kg, averaged over one gram of human tissue, the limit for every new mobile handset design sold in India. Before that India followed the older figure of 2.0 W/kg averaged over ten grams. The rules also require the SAR value to be printed on the handset and its box, and a buyer can check it by dialling a code given by the maker. India's limit matches the standard used in the United States. Option A is wrong because 1.8 W/kg is not a prescribed limit anywhere. Option B is wrong because 2.1 W/kg is not a SAR standard. Option C is wrong because 2.2 W/kg is only a distractor. Exam tip: India's SAR limit is 1.6 W/kg over 1 gram of tissue, in force from 1 September 2012.

The correct answer is C, the number of holes equals the number of electrons. In an intrinsic, that is a chemically pure, semiconductor every free electron is produced by breaking a covalent bond, and breaking a bond leaves behind exactly one hole, so electrons and holes are created strictly in pairs and their concentrations must be equal. Option A is wrong because a product of two concentrations cannot equal a bare number one; the product is fixed by temperature and the band gap, not by unity. Option B is wrong because holes can outnumber electrons only in a p-type crystal, which needs a trivalent dopant. Option D is wrong because electrons outnumber holes only in an n-type crystal, which needs a pentavalent dopant. Equal numbers are therefore the signature of the pure crystal, and any inequality means doping has taken place.

The correct answer is A, the Research Designs and Standards Organisation, usually written as RDSO. It is the research, design and standards wing of Indian Railways, has its headquarters at Lucknow, and developed Kavach in partnership with Indian manufacturers, first under the name Train Collision Avoidance System. Option B, the Centre for Railway Information Systems, builds and runs the computer systems of the Railways, such as passenger reservation and freight information, and does not design signalling hardware. Option C, the Indian Railway Catering and Tourism Corporation, handles catering, online ticketing and tourist trains. Option D, the Dedicated Freight Corridor Corporation of India, was set up to build and manage the Eastern and Western freight corridors. All four are genuine railway bodies, which is why the question is a test of what each one actually does.

The correct answer is C, 1950. Alan Turing set out the imitation game in his paper Computing Machinery and Intelligence, published in 1950 in the journal Mind; a machine passes if a human judge, exchanging only typed messages, cannot tell it from a human being. Option A is wrong because 1936 is the year of Turing’s earlier and quite different paper on computable numbers, which described the theoretical Turing machine, the foundation of computability rather than a test for intelligence. Option B is wrong because 1943 is associated with the McCulloch and Pitts model of an artificial neuron, the first mathematical model of a neural network. Option D is wrong because 1956 is the year of the Dartmouth Conference, where the term artificial intelligence was coined. Examiners pair 1950 with the test and 1956 with the name, so keep the two dates apart.

The correct answer is B, Homi Jehangir Bhabha. Bhabha founded the Tata Institute of Fundamental Research in 1945, became the first chairman of the Atomic Energy Commission in 1948, drew up the three stage plan built around India's thorium, and led the establishment at Trombay that was renamed the Bhabha Atomic Research Centre after his death in 1966. Option A is wrong because Vikram Sarabhai is the father of the Indian space programme, although he did chair the Atomic Energy Commission after Bhabha. Option C is wrong because Raja Ramanna led the team that carried out the Pokhran test of 1974, an important role but a later one. Option D is wrong because A. P. J. Abdul Kalam is associated with missile development and with the Pokhran tests of 1998. Bhabha for atomic energy and Sarabhai for space is the pair to fix.

The correct answer is C, phosphorus. Silicon has four valence electrons, so adding a pentavalent atom such as phosphorus, arsenic, antimony or bismuth leaves one electron over after four bonds are formed; that spare electron is loosely held and becomes a free carrier, making electrons the majority carriers and the crystal n-type. Option A is wrong because boron is trivalent and creates a vacancy, giving a p-type crystal. Option B is wrong because aluminium is also trivalent and is another p-type dopant. Option D is wrong because indium is trivalent as well. Note that an n-type crystal is not negatively charged: the donor atom keeps its positive nucleus, so the crystal as a whole stays electrically neutral, and examiners test exactly this point in statement-based questions.

The correct answer is B, vitamin A. Golden rice was engineered to make beta carotene, the precursor from which the body forms vitamin A, in the edible part of the grain, and the pigment gives the rice its golden colour; the aim was to reduce night blindness among populations living mainly on rice. Option A is wrong because iron deficiency is addressed by biofortified varieties of pearl millet and wheat and by fortified foods, not by golden rice. Option C is wrong because iodine deficiency is tackled by iodised salt, a public health measure that needs no engineering of the crop. Option D is wrong because vitamin D is obtained largely from sunlight and from fortified milk. Golden rice is the standard example of biofortification by genetic engineering.

The correct answer is C, supervised learning. Here every training example carries the right answer, its label, and the model learns the mapping from input to label, which is how spam filters, handwriting readers and credit-scoring models are built. Option A is wrong because unsupervised learning is given data without labels and must find structure by itself, typically clustering or dimensionality reduction; customer segmentation is the standard example. Option B is wrong because reinforcement learning has neither labels nor fixed answers: an agent acts in an environment and learns from rewards and penalties, the method behind game-playing programs and robot control. Option D is wrong because transfer learning is not a third style of its own but a technique of reusing a model trained on one task as the starting point for another. Remember the pairing: labels mean supervised, no labels mean unsupervised, rewards mean reinforcement.

The correct answer is B, John McCarthy. The American computer scientist John McCarthy is called the father of artificial intelligence because he coined the term itself in his proposal for the Dartmouth summer research project of 1956, the meeting at which the field was born. He also created LISP in 1958, the language in which most early artificial intelligence work was written, argued for time sharing on computers, and received the Turing Award in 1971. Option A is wrong because Alan Turing is honoured as the father of computer science and of the Turing test, which asks whether a machine can be told apart from a person in conversation, but he did not name the subject. Option C is wrong because Blaise Pascal built the Pascaline, a mechanical adding machine, in the seventeenth century. Option D is wrong because Dartmouth is the college where the 1956 conference was held, not a person. Exam tip: McCarthy named artificial intelligence in 1956 and wrote LISP.

The correct answer is B, holes. A trivalent dopant such as boron, aluminium, gallium or indium forms only three covalent bonds with the surrounding silicon atoms, leaving one bond incomplete; that vacancy behaves as a mobile positive carrier called a hole, and holes therefore become the majority carriers while thermally generated electrons remain the minority carriers. Option A is wrong because electrons are the majority carriers in an n-type crystal and only the minority carriers here. Option C is wrong because protons are bound inside nuclei and never move through a crystal lattice. Option D is wrong because the dopant ions are fixed in the lattice and cannot carry current, even though they are charged. Remember also that a p-type crystal is electrically neutral overall, exactly like an n-type crystal.

The correct answer is A, the Vikram Sarabhai Space Centre at Thiruvananthapuram, ISRO's lead centre for launch vehicle design and development, including solid propulsion, aerodynamics and vehicle structures. Its companion, the Liquid Propulsion Systems Centre, develops the liquid and cryogenic engines that those vehicles fly with.

Option B, the National Remote Sensing Centre at Hyderabad, receives, processes and distributes satellite imagery. Option C, the Master Control Facility at Hassan in Karnataka, does not build anything: it controls geostationary satellites once they are in orbit. Option D, the Physical Research Laboratory at Ahmedabad, founded by Vikram Sarabhai in 1947, carries out space science research and is the cradle of the Indian space programme rather than a rocket factory. Match each centre to one verb: develop, receive, control, research.

The correct answer is A, about Rs 10,372 crore. The Union Cabinet approved the IndiaAI Mission on 7 March 2024 with an outlay of 10,371.92 crore rupees, to be spent across its seven components, and the mission is run by the IndiaAI Independent Business Division under the Digital India Corporation in the Ministry of Electronics and Information Technology. Option B is wrong because 76,000 crore rupees is the outlay of the Semicon India programme for semiconductor and display manufacturing, approved in December 2021, a figure examiners deliberately place beside this one. Option C is wrong because 1,500 crore rupees is far too small for a mission that has to buy or hire tens of thousands of GPUs. Option D is wrong because 25,000 crore rupees matches no approved outlay for this mission. Learn the pair: IndiaAI about 10,372 crore, Semicon India 76,000 crore.

The correct answer is A, Bardeen, Brattain and Shockley. John Bardeen, Walter Brattain and William Shockley built the first working transistor at Bell Laboratories in the United States in 1947, and the three shared the Nobel Prize in Physics in 1956 for the discovery of the transistor effect; the device replaced the bulky vacuum tube and made all later electronics possible. Option B is wrong because Jack Kilby and Robert Noyce independently developed the integrated circuit in 1958 and 1959, and Gordon Moore gave the industry its famous doubling rule. Option C is wrong because Faraday, Maxwell and Hertz belong to the history of electromagnetism. Option D is wrong because Townes, Basov and Prokhorov won the Nobel Prize of 1964 for work on the maser and the laser.

The correct answer is C, seven. The approved mission has seven components: IndiaAI Compute Capacity, the IndiaAI Innovation Centre, the IndiaAI Datasets Platform, the IndiaAI Application Development Initiative, IndiaAI FutureSkills, IndiaAI Startup Financing, and Safe and Trusted AI. Option A is wrong, and five is a tempting answer because NITI Aayog’s National Strategy for Artificial Intelligence of 2018 named five focus sectors, namely healthcare, agriculture, education, smart cities and infrastructure, and smart mobility; that five belongs to the strategy, not to the mission. Option B is wrong because six leaves one pillar out, usually Safe and Trusted AI, which is the one most often asked about separately. Option D is wrong because nine matches no official list. The safe way to remember it is compute, models, data, applications, skills, money and safety, which is exactly seven.

The correct answer is A, collector current to emitter current. In a bipolar junction transistor the emitter injects carriers, the thin lightly doped base lets most of them through, and the collector gathers them, so the emitter current divides into a large collector current and a small base current; alpha is defined as the collector current divided by the emitter current and is therefore always a little less than one, typically between 0.95 and 0.99. Option B is wrong because it inverts the ratio and would give a value greater than one. Option C is wrong because the base to collector ratio is a small fraction with no standard name. Option D is wrong because the collector current divided by the base current is beta, the current gain, which runs into the tens or hundreds. Keep alpha below one and beta well above one.