Science & Technology Mixed Quiz: Set 31

The correct answer is C, the Liability Convention, 1972. Its full name is the Convention on International Liability for Damage Caused by Space Objects, and it fixes responsibility on the state that launches or procures the launch of a space object. Liability is absolute for damage caused on the surface of the Earth or to aircraft in flight, and fault based for damage caused elsewhere, such as a collision between two satellites in orbit.

Option A, the Outer Space Treaty of 1967, is the foundational instrument that declares space free for exploration by all, bans weapons of mass destruction in orbit and bars national appropriation of celestial bodies; it states the principle of state responsibility but the detailed liability rules came later. Option B, the Rescue Agreement of 1968, deals with the return of astronauts and space objects. Option D, the Moon Agreement of 1979, covers activities on the Moon and other bodies and has very few parties.

The correct answer is C, Both 1 and 2. LiFi (Light Fidelity) sends data wirelessly by switching LED light on and off far too fast for the eye to notice, and it can be many times faster than WiFi.

The idea was popularised by Professor Harald Haas of the University of Edinburgh in 2011. A LiFi bulb flickers at very high frequency, and a photodetector reads these changes as binary data. Because visible light has a far wider spectrum than the radio waves used by WiFi, laboratory tests have reached speeds many times higher than WiFi. Light cannot pass through walls, which limits range but makes the signal harder to intercept and free of radio interference, useful in hospitals and aircraft.

A is wrong because statement 2 is also correct.

B is wrong because statement 1, the use of light, is the very basis of LiFi.

D is wrong because both statements describe LiFi correctly.

Exam tip: WiFi uses radio waves; LiFi uses visible light from LEDs and cannot pass through walls.

The correct answer is B, the National Institute of Ocean Technology, Chennai. This autonomous institute of the Ministry of Earth Sciences designs and builds India's ocean engineering hardware, from desalination plants and moored buoys to deep-sea mining systems, and it is developing Matsya-6000 along with the systems that will support the dives.

Option A, the space agency, contributes expertise on welding and testing of the titanium sphere and on launch-grade materials, which is why it is a plausible wrong answer, but the submersible is not its project. Option C, the polar and ocean research centre in Goa, runs the polar expeditions and the Southern Ocean programme rather than vehicle development. Option D, the ocean information services centre in Hyderabad, issues ocean advisories and runs the tsunami early warning centre. All four bodies appear in this topic, so attach each to its own function.

The correct answer is B, Schirmacher Oasis in Queen Maud Land. Maitri was commissioned in 1989 on the rocky Schirmacher Oasis, a narrow ice-free strip, next to the freshwater lake named Priyadarshini. Standing on rock rather than on ice is precisely why Maitri has survived while the earlier station on the ice shelf did not.

Option A, Larsemann Hills, is the site of Bharati, India's third station, commissioned in 2012 on the east Antarctic coast, and swapping the two sites is the commonest error here. Option C, Ny-Alesund in Svalbard, is in the Arctic and is the site of Himadri, not of any Antarctic station. Option D, the Ross Ice Shelf, is a well known Antarctic feature on the other side of the continent where several other countries have bases, but India has never built there. Fix the pair: Maitri at Schirmacher, Bharati at Larsemann.

The correct answer is B, Wilhelm Conrad Roentgen. Working with a discharge tube at the University of Wurzburg in November 1895, Roentgen noticed that a screen coated with a fluorescent salt glowed even when the tube was covered, and he traced the effect to an unknown penetrating radiation that he called X-radiation. For this he received the first Nobel Prize in Physics, awarded in 1901.

Option A, Marie Curie, with Pierre Curie discovered polonium and radium and won Nobel Prizes in Physics in 1903 and in Chemistry in 1911, but her work was on radioactivity and not on X-rays. Option C, Henri Becquerel, discovered natural radioactivity in uranium salts in 1896, a year after Roentgen, and his discovery was in fact prompted by the news about X-rays. Option D, J. J. Thomson, discovered the electron in 1897. Keep the sequence in mind: X-rays in 1895, radioactivity in 1896, the electron in 1897.

The correct answer is B, one sidereal day, 23 hours 56 minutes 4 seconds. A geostationary satellite must match the rotation of the Earth with respect to the distant stars, and that rotation takes one sidereal day. Matching the solar day of twenty-four hours would leave the satellite drifting slowly, because the solar day includes the extra turn needed to face the Sun again as the Earth moves along its orbit.

Option A, exactly 24 hours, is the answer most candidates give and is accepted loosely in general conversation, but in a careful question the sidereal figure is the right one. Option C, 12 hours, is roughly the period of a navigation satellite in medium Earth orbit and of a Molniya orbit. Option D, about 90 minutes, is the period of a satellite in low Earth orbit, such as a space station at around 400 kilometres. The rule behind all of this is that orbital period increases with orbital height.

The correct answer is B, Battery Electric Vehicle. A BEV carries no engine at all; it runs entirely on a traction battery that is charged from an external electricity supply, and it has no tailpipe emissions. The other three abbreviations in the same family are HEV for a hybrid electric vehicle, which has an engine and a small battery but no plug, PHEV for a plug-in hybrid, and FCEV for a fuel cell electric vehicle running on hydrogen.

Option A is an invented expansion, as is option D; a bi-fuel vehicle is one that can run on two fuels such as petrol and compressed natural gas, which is a different idea altogether and not an electric vehicle. Option C is wrong, though the word Bharat does appear in Indian charging standards such as Bharat AC-001 and Bharat DC-001. Learn the four categories as a set, because questions frequently describe one of them and ask you to name it.

The correct answer is A, Prarambh. Skyroot Aerospace named the maiden flight of Vikram-S Mission Prarambh, a Sanskrit word meaning beginning, because it was the first flight by a private Indian rocket. The vehicle rose on a sub-orbital path from a launch pad at the Satish Dhawan Space Centre and carried three small customer payloads. Option B is wrong because SOrTeD, short for Sub-Orbital Technology Demonstrator, is the name of the Agnikul Cosmos flight of Agnibaan in 2024, a different company and a different year. Option C is wrong because Pragyan is the name of the rover carried by India's Chandrayaan missions to the Moon. Option D is wrong because Prathama is not the name of any Indian space mission, and is included only as a plausible-sounding distractor.

The correct answer is C, 25 years. The long-standing guideline of the Inter-Agency Space Debris Coordination Committee, formed in 1993 and including ISRO among its member agencies, is that a spacecraft or upper stage leaving the low Earth orbit protected region should be de-orbited, or placed in an orbit from which it will re-enter, within twenty-five years after the mission ends. Along with this goes passivation, that is venting leftover propellant and discharging batteries so that the hardware cannot explode and create fresh fragments.

Option A, 5 years, and option B, 10 years, are shorter than the accepted figure, although newer national rules in some countries now push towards tighter timelines. Option D, 50 years, is far too long to be useful, because debris lingering that long in a crowded band keeps the collision risk high. For geostationary satellites the corresponding practice is not de-orbiting but raising the satellite into a graveyard orbit above the belt.

The correct answer is C, Proof of Work. In proof of work, the computers called miners compete to find a nonce that makes the hash of the proposed block meet a difficulty target. The search requires enormous numbers of trials and therefore real electricity, which is the cost that makes rewriting the chain uneconomic; the winner adds the block and receives the block reward and the fees. Option A is wrong because proof of stake, in which validators are chosen in proportion to the coins they lock up, is used by Ethereum after its change of mechanism in 2022 and by many newer chains, but not by bitcoin. Option B is wrong because proof of authority relies on a small set of identified validators and suits private or consortium chains. Option D is wrong because practical Byzantine fault tolerance is a voting-based mechanism used in permissioned systems such as Hyperledger Fabric.

The correct answer is A, the Central Indian Ocean Basin. India was the first country to be granted Pioneer Investor status by the International Seabed Authority, in 1987, and holds an exploration area of seventy-five thousand square kilometres in the Central Indian Ocean Basin for polymetallic nodules, which are lumps on the deep seabed rich in manganese, nickel, cobalt and copper.

Option B, the Bay of Bengal shelf, and option C, the Arabian Sea shelf, lie within India's own maritime zone and are shallow continental shelves where nodules of this kind do not form; they are fishing and hydrocarbon areas instead. Option D, the Clarion-Clipperton Zone in the Pacific, is the world's richest nodule province and is contracted to several other countries, which makes it the best distractor. India also holds a contract for polymetallic sulphides along the Central and Southwest Indian Ridges.

The correct answer is B, an earthen pitcher. The Eco Mark scheme was notified in 1991 for consumer products that cause the least harm to the environment over their life, and the earthen pitcher was chosen as the symbol because it is made from a renewable material, is produced without generating waste, uses little energy and is wholly biodegradable when broken. The criteria for each product category are framed with the Ministry of Environment, Forest and Climate Change, and the mark itself is awarded by the Bureau of Indian Standards along with the ISI mark. Options A, C and D are wrong because no such symbol was adopted for the scheme; a leaf, a river and a peacock feather are generic images of nature used in various logos, and candidates pick them by guesswork. The pitcher is the single fact to remember here.

The correct answer is C, magnetic resonance imaging. MRI works by placing the hydrogen nuclei of the body in a strong static magnetic field and disturbing them with radiofrequency pulses, which lie in the harmless low-energy part of the electromagnetic spectrum. No ionising radiation is involved, which is why MRI can be repeated as often as the physician wishes.

Option A, plain radiography, uses X-rays, which are ionising by definition because they carry enough energy to knock electrons out of atoms. Option B, computed tomography, uses the same X-rays from many angles and delivers a larger dose than a single film. Option D, positron emission tomography, injects a radioactive tracer whose positrons annihilate with electrons to release gamma photons, so it too is ionising. Ultrasound is the other common technique that avoids ionising radiation, which is why ultrasound and MRI are preferred in pregnancy.

The correct answer is C, Admiral Gorshkov. INS Vikramaditya is a modified Kiev class ship of Soviet origin, formerly named Admiral Gorshkov, which was rebuilt in Russia and handed over to India, entering service as an aircraft carrier operating MiG-29K fighters. Option A, HMS Hercules, was the British ship that India completed and commissioned in 1961 as the first INS Vikrant. Option B, HMS Hermes, was the British carrier that served India as INS Viraat until 2017. Option D is not the name of any Indian carrier. The full line of Indian carriers is therefore the first Vikrant from 1961, Viraat, Vikramaditya and the new indigenous Vikrant of 2022, and papers often ask which of them was built in India, the answer being only the last.

The correct answer is A, John Goodenough, Stanley Whittingham and Akira Yoshino. Whittingham built the first working lithium cell in the 1970s, Goodenough found that a lithium cobalt oxide cathode could give a far higher voltage, and Yoshino replaced the dangerous metallic lithium anode with a carbon material, producing the safe, rechargeable cell that was commercialised in 1991. Goodenough, then aged ninety-seven, became the oldest person to receive a Nobel Prize.

Option B names the laureates of the 2000 Chemistry prize for conductive polymers. Option C names the 2013 Chemistry laureates, honoured for computer models of chemical processes. Option D names the 2020 Chemistry laureates, awarded for the CRISPR method of genome editing. The pairing to remember is the year 2019, the subject Chemistry and the three names, since the question is almost always asked in exactly this form.

The correct answer is B, Data Principal. The Act of 2023 calls the individual to whom the personal data relates the Data Principal, and gives that person rights of access, correction, erasure and grievance redressal. Option A is wrong and is the commonest confusion: a Data Fiduciary is the person or entity that decides the purpose and means of processing the data, and it carries the duties under the Act. Option C is wrong because a Consent Manager is an entity registered with the Data Protection Board through which a Data Principal can give, manage and withdraw consent. Option D is wrong since a Data Processor processes data on behalf of a Data Fiduciary. The Act follows the Puttaswamy judgment of 2017 and the report of the Justice B. N. Srikrishna Committee.

The correct answer is B, Himachal Pradesh. Himansh was established in 2016 in the Spiti area of Himachal Pradesh, in the upper reaches of the Chandra basin, so that scientists can measure the mass balance, melt and movement of Himalayan glaciers through the year instead of only on short visits. The Himalayan cryosphere is often called the third pole, which is why this station sits in the same programme as the polar stations.

Option A, Uttarakhand, has many studied glaciers, including Gangotri, but not this station. Option C, Sikkim, and option D, Ladakh, also have glaciers under observation but no station of this name. Do not confuse Himansh in the Himalaya with Himadri in the Arctic; the names differ by two letters and the two stations are at opposite ends of this topic, one in Svalbard since 2008 and the other in Spiti since 2016.

The correct answer is B, computed tomography. The Hounsfield unit, named after Godfrey Hounsfield, expresses how strongly a small volume of tissue attenuates X-rays, on a scale fixed by definition at zero for water and minus one thousand for air. Fat falls below zero, soft tissue a little above it, and dense bone runs to a thousand and beyond, which lets a radiologist judge tissue type from the numbers alone.

Option A is wrong because MRI images are described by signal intensity and sequence weighting, not by a fixed absolute scale. Option C is wrong because ultrasound images are described by echogenicity, with terms such as hyperechoic and anechoic, and the useful measurement is the Doppler velocity of flow. Option D is wrong because electrocardiography records voltages against time in millivolts and produces a trace, not an image. Pair the names in revision: Hounsfield with CT, tesla with MRI, megahertz with ultrasound.

The correct answer is A, graphite. The layered structure of graphite can accept lithium ions between its sheets, a process called intercalation, and release them again without breaking down, which is what makes the cell rechargeable over hundreds of cycles. Using carbon instead of metallic lithium for this electrode was Akira Yoshino's contribution and is the reason the cell is safe enough for consumer use.

Option B, lithium cobalt oxide, is a cathode material, not an anode; it belongs on the positive side, along with lithium iron phosphate and nickel manganese cobalt oxides. Option C, zinc, is the anode of a dry cell and of alkaline cells. Option D, lead dioxide, is the positive plate of the lead-acid battery used for starting engines, whose negative plate is spongy lead. Fix the pair in mind: graphite anode and lithium metal oxide cathode, with a lithium salt in an organic solvent as the electrolyte.

The correct answer is C, it will be halved. The cutoff or minimum wavelength of the continuous X-ray spectrum arises when an electron gives up its entire kinetic energy in a single collision with the target. Equating the work done by the accelerating voltage with the photon energy gives the relation that the minimum wavelength equals the product of Planck's constant and the speed of light divided by the electronic charge and the voltage. The wavelength is therefore inversely proportional to the applied voltage, so doubling the voltage halves it. This is the Duane-Hunt law.

Option A is wrong because the cutoff depends only on the voltage, which has changed. Option B inverts the relationship and is the commonest error. Option D would follow from an inverse square dependence, which does not apply here. Note also what does not matter: the separation between filament and target and the target material affect intensity and the characteristic lines, not the cutoff wavelength.