CDS 2022 Previous Year GK Questions with Answers

The correct answer is C, increases heavily. In a short circuit the live and neutral wires touch, the resistance of the path falls almost to zero, and the current shoots up.

By Ohm's law, current I = V / R. Normally the appliances in a circuit provide resistance and keep the current within safe limits. When damaged insulation lets the live wire touch the neutral wire directly, the current bypasses the appliances and the resistance becomes very small, so for the same supply voltage the current becomes very large. This heats the wires sharply (heat ∝ I²Rt) and can start a fire. A fuse or a miniature circuit breaker (MCB) breaks the circuit when this happens.

A is wrong: lower resistance means more current, not less.

B is wrong: the resistance changes sharply, so the current cannot stay the same.

D is wrong: the current does not fluctuate; it rises to a very high value until a fuse or breaker cuts it.

Exam tip: short circuit means resistance near zero and huge current; overloading means too many appliances on one socket.

The correct answer is B, Desert, Tropical thorny, Moist deciduous, Mangrove. The route runs from the dry west to the wet east coast, so the vegetation changes as rainfall rises.

Bikaner lies in the Thar Desert of western Rajasthan, where rainfall is below about 25 cm and only desert plants such as khejri and cactus grow. Moving east through eastern Rajasthan and the drier parts of central India, rainfall of roughly 25 to 70 cm supports tropical thorn forests of acacia, babool and ber. Further east, in Chhattisgarh, Jharkhand and Odisha, rainfall of about 100 to 200 cm supports moist deciduous forests of sal and teak. Konark is on the Odisha coast near the Mahanadi delta, where tidal creeks support mangroves.

A is wrong: it puts thorny vegetation before the desert, but Bikaner itself is in the desert.

C is wrong: it starts with moist deciduous forest and ends with desert, the reverse of the journey.

D is wrong: mangroves grow only at the coast, so they must come last, after the inland deciduous forests.

Exam tip: more rain, richer forest: desert < thorn < dry deciduous < moist deciduous < evergreen; mangroves on tidal coasts.

The correct answer is A, Silver < Nichrome < Glass. Silver is the best conductor, nichrome is an alloy with high resistivity, and glass is an insulator with enormous resistivity.

Resistivity is a property of the material itself, measured in ohm-metre. At room temperature silver has about 1.6 × 10⁻⁸ Ω m, the lowest of all metals, which is why it conducts electricity better than copper. Nichrome, an alloy of nickel and chromium, has about 1.1 × 10⁻⁶ Ω m, roughly a hundred times more than silver, so it is used for the heating coils of irons, toasters and heaters. Glass has a resistivity of about 10¹⁰ to 10¹⁴ Ω m, so it hardly conducts at all.

B is wrong: it reverses the order and puts the insulator first.

C is wrong: glass resists current far more than nichrome, so it cannot come in the middle.

D is wrong: nichrome has much higher resistivity than silver, not lower.

Exam tip: conductors (silver, copper) < alloys (nichrome, manganin) < insulators (glass, rubber).

The correct answer is B, Singareni Collieries Company Limited. Incorporated in 1920 and later taken over by the government, SCCL is India's oldest government-owned coal mining company.

Coal was found in the Godavari valley near Yellandu in the 1870s, and the Hyderabad (Deccan) Company began mining there in 1886. In 1920 it became The Singareni Collieries Company Limited, a public limited company, and the Hyderabad State government bought a majority of its shares in 1945. Today the Government of Telangana holds 51% and the Government of India 49%. It mines in the Godavari valley coalfields of Telangana.

A is wrong: Neyveli Lignite Corporation was set up in 1956 to mine lignite in Tamil Nadu.

C is wrong: Coal India Limited was formed in 1975, after the coal mines were nationalised in 1971–73.

D is wrong: Mahanadi Coalfields Limited is a subsidiary of Coal India created in 1992 for the Odisha coalfields.

Exam tip: SCCL 1920 (Telangana, oldest); NLC 1956; Coal India 1975; MCL 1992.

The correct answer is A, Morley-Minto Reforms, 1909. This Act, formally the Indian Councils Act of 1909, first gave Muslims a separate electorate, in which Muslim voters chose Muslim members from Muslim-only constituencies. Lord Minto was the Viceroy and John Morley the Secretary of State, and the step came after the Simla deputation of 1906 and the founding of the Muslim League that year. It also enlarged the legislative councils and let Indians sit on the Viceroy's executive council for the first time, Satyendra Prasad Sinha being the first. Nationalists called the measure communal, since it made religion the basis of representation. Option B is wrong because the reforms of 1919 only extended separate electorates to Sikhs, Indian Christians, Anglo-Indians and Europeans. Option C is wrong because the Communal Award of 1932 added separate electorates for the depressed classes. Option D is wrong because the Act of 1935 continued the system rather than creating it. Exam tip: Minto is remembered as the father of communal electorates, 1909.

The correct answer is C, Parushni, the Vedic name of the river we now call the Ravi. The Battle of Ten Kings, or Dasarajna, is described in the seventh book of the Rigveda. Sudas, the Bharata king of the Tritsu clan, was attacked by a confederacy of ten chiefs led by the Puru tribe, and with his priest Vasishtha guiding him he defeated them on the banks of the Parushni. The victory made the Bharatas the leading power of the Sapta Sindhu and later gave the land the name Bharatavarsha. Option A is wrong because the Sarasvati was the river the Rigveda praises most as sacred, but no such battle is placed on it. Option B is wrong because the Drishadvati, paired with the Sarasvati in the later Brahmavarta region, is not the site either. Option D is wrong because the Shutudri is the Sutlej. Exam tip: Parushni is the Ravi, Vitasta the Jhelum, Askini the Chenab, Vipasha the Beas and Shutudri the Sutlej.

The correct answer is C, 6. The balanced equation for the complete combustion of glucose is C6H12O6 plus 6O2 gives 6CO2 plus 6H2O, so one mole of glucose needs six moles of oxygen gas. Balancing it is quick: glucose has six carbon atoms, so six molecules of carbon dioxide are formed, and its twelve hydrogen atoms give six molecules of water. That calls for eighteen oxygen atoms on the right, and since glucose itself supplies six, the remaining twelve must come from oxygen gas, which is six molecules of O2. The same reaction runs in our cells as aerobic respiration and releases about 2870 kilojoules of energy per mole of glucose. Option A is wrong because one mole of oxygen could not even oxidise the carbon present. Option B is wrong because three moles would leave the reaction half complete, giving carbon monoxide instead. Option D is wrong because twelve moles counts oxygen atoms, not molecules. Exam tip: for glucose the carbon dioxide, water and oxygen coefficients are all 6.

The correct answer is A, A snow covered mountain. Albedo is the share of incoming sunlight a surface reflects back, and fresh snow reflects the most of any natural surface on land. Clean new snow has an albedo of about 80 to 90 per cent, which is why snowfields stay cold and why sunlight on them hurts the eyes. The colour and roughness of a surface decide its albedo: pale, smooth surfaces throw light back, while dark, rough ones soak it up. This matters for climate because melting snow and ice expose darker ground, which absorbs more heat and speeds up further melting. Option B is wrong because bare rock reflects only about 10 to 25 per cent. Option C is wrong because dry sand reflects roughly 25 to 40 per cent, high but well below snow. Option D is wrong because a mangrove forest has the lowest albedo here, around 10 to 15 per cent, as its dark canopy traps light. Exam tip: snow highest, forest and ocean lowest, earth's average albedo about 30 per cent.

The correct answer is D. Setting up an institution in India means putting money into a real asset and running it, which is exactly what Foreign Direct Investment is. FDI is lasting investment that brings control or a significant say in the management of an Indian enterprise, usually through a new unit, a factory, a subsidiary or a large stake in an existing company. It also brings technology, jobs and management practice, and it cannot be pulled out overnight. The other three options all describe Foreign Portfolio Investment, where an outsider buys listed shares or bonds purely for returns, takes no part in management and can sell on any trading day. Options A, B and C are therefore wrong for the same reason: buying shares on a stock exchange, whether by a company, a pension fund or a merchant banker, is portfolio investment. Exam tip: FDI means control and a factory on the ground, FPI means hot money that can leave quickly.

The correct answer is D, salinity. An isohaline joins points of equal salinity on a map, and the name comes from the Greek halos, meaning salt. Such lines let geographers show how salty different parts of the ocean are. Average ocean salinity is about 35 parts per thousand, but it varies: enclosed hot seas like the Red Sea cross 40 parts per thousand, while the Baltic Sea falls below 10 because rivers pour fresh water into it. Salinity is highest in the subtropics, where evaporation beats rainfall, and lower near the equator and the poles. Option A is wrong because lines of equal temperature are isotherms. Option B is wrong because lines of equal pressure are isobars, drawn on every weather map. Option C is wrong because lines of equal rainfall are isohyets. Exam tip: learn the set together - isotherm for temperature, isobar for pressure, isohyet for rainfall, isohaline for salinity and isohel for sunshine.

The correct answer is B. The British wanted Russian influence kept out of Kabul, but they did not want a strong Afghan state on the north-west frontier either, because a powerful neighbour would be hard to control. This twin aim is part of the Great Game, the long rivalry between Britain and Russia over Central Asia. Lord Auckland acted on it in the First Anglo-Afghan War of 1838 to 1842, replacing Dost Mohammad with Shah Shuja; the occupation ended in a disastrous retreat from Kabul. The policy settled into keeping Afghanistan weak, divided and dependent, a cushion rather than an ally. Option A is wrong because Britain deliberately avoided building up Afghan strength. Option C is wrong because keeping Russia out, not inviting it in, was the whole point of the policy. Option D is wrong because Afghanistan was never annexed; the two Anglo-Afghan wars of this century ended in withdrawal. Exam tip: First Anglo-Afghan War, 1838 to 1842, under Lord Auckland, and the Great Game against Russia.

The correct answer is C, Purva Mimamsa. Purva Mimamsa is the school founded by Jaimini, which treats the karma kanda or ritual portion of the Vedas as authoritative and holds that liberation follows from the correct performance of Vedic duty. Kumarila Bhatta and Prabhakara are its two great commentators, and the school divides into the Bhatta and the Prabhakara traditions after them. Option A, Lokayata, is the materialist Charvaka school, which denies the Vedas altogether and therefore cannot claim either thinker. Option B, Madhyamika, is a Mahayana Buddhist school associated with Nagarjuna and his doctrine of shunyata, from a wholly different tradition. Option D, Uttara Mimamsa, is another name for Vedanta, the school of the jnana kanda and of the Upanishads, whose commentators are Shankaracharya, Ramanuja and Madhvacharya; it is the strongest distractor because the two Mimamsas share a name.

The correct answer is D, all four. A bicameral State legislature has a Legislative Assembly and a Legislative Council, and Andhra Pradesh, Telangana, Bihar and Uttar Pradesh each have both Houses. Options A, B and C are wrong because each of them leaves out a State that does have a Council. Bihar has had a Council since before independence and Uttar Pradesh is the largest of the bicameral States; Andhra Pradesh revived its Council by an Act of Parliament, and Telangana received one when it was carved out of Andhra Pradesh in 2014. The Governor is central to this arrangement: under Article 168 he is part of the legislature, under Article 171 he nominates one-sixth of the Council, and under Article 169 no Council can be created or abolished unless the Assembly passes a special-majority resolution and Parliament then makes a law.

The correct answer is To value and preserve a unitary national culture. Article 51A(f) actually asks citizens "to value and preserve the rich heritage of our composite culture". The word matters: India's culture is described as composite, a blend of many traditions, languages and faiths, not a single unitary culture. By changing one word, the examiner turns a real duty into a false one.

The other three options are genuine duties. Rendering national service when called upon to do so is part of clause (d). Renouncing practices derogatory to the dignity of women is part of clause (e), which also asks citizens to promote harmony across religious, linguistic and regional diversities. Developing the spirit of inquiry and reform is part of clause (h), along with the scientific temper and humanism. This question is a reminder to learn the exact wording of the duties, because CDS and UPSC papers often test a single changed word rather than the whole idea.

The correct answer is D, Proteins. Kwashiorkor is caused by a severe lack of protein in the diet, even when the child gets some calories from starchy food. It usually strikes children aged one to five after they stop breastfeeding and are fed mostly rice, maize or cassava. The tell-tale signs are a swollen belly and puffy legs due to fluid retention (oedema), a moon face, peeling skin, thin reddish hair and poor growth. The word comes from Ghana and is often explained as the sickness of the older child pushed off the breast when a new baby arrives. Its cousin marasmus comes from a lack of both protein and calories and leaves the child wasted, with no swelling. A is wrong, because mineral shortages cause other diseases, such as anaemia from lack of iron and goitre from lack of iodine. B is wrong, because vitamin deficiencies cause scurvy, rickets and night blindness, not kwashiorkor. C is wrong, because a lack of fat is not what causes kwashiorkor. Exam tip: kwashiorkor, protein only, swollen belly; marasmus, protein and calories, wasting.

The correct answer is C, erect, virtual and larger than the object. For a lens, magnification m is the image height divided by the object height, which also equals v divided by u. A plus sign means the image is erect and virtual, and a value of 2 means it is twice as tall as the object. Only a convex lens can form such an image, when the object is placed between the optical centre and the principal focus; this is exactly how a magnifying glass or a simple microscope works. A concave lens also forms erect, virtual images, but they are always smaller, so its magnification stays between 0 and plus 1. A is wrong, because an erect, virtual, smaller image needs m between 0 and 1, as with a concave lens. B is wrong, because a real, inverted image always has a negative magnification. D is wrong, because a real, inverted, enlarged image would have m below minus 1, such as minus 2. Exam tip: the sign tells the type, plus for virtual and erect, minus for real and inverted; a value above 1 means enlarged.

The correct answer is A, Any privately held startup company with a value of over $1 billion. A unicorn is a startup that is not listed on the stock market and is valued at more than one billion US dollars. The term was coined in 2013 by the American venture capitalist Aileen Lee, who picked the mythical animal because such startups were then very rare. Related words follow the same pattern: a decacorn is valued at over 10 billion dollars and a hectocorn at over 100 billion dollars. Once a unicorn lists its shares through an IPO, it becomes a listed company and, strictly speaking, is no longer called a unicorn. B is wrong, because merging one public sector company with another, as done with several public sector banks, is consolidation. C is wrong, because selling a loss-making state-owned company is privatisation or disinvestment. D is wrong, because a foreign firm working with an Indian partner forms a joint venture. Exam tip: unicorn, private startup, over 1 billion dollars; decacorn, over 10 billion.

The correct answer is C, Sikkim. Tsomgo Lake, also called Changu Lake, lies in East Sikkim, about 40 km from Gangtok on the road to Nathu La. It is a glacial lake at a height of roughly 3,750 metres; it freezes in winter and is fed by melting snow in summer, which makes it one of Sikkim's best-known tourist spots. In the local language tso means lake, the same word you see in the names of Ladakh's lakes. Nathu La, the pass just beyond it, is a point for border trade with the Tibet region of China. A is wrong, because Ladakh's famous high lakes are Pangong Tso and Tso Moriri, not Tsomgo. B is wrong, because Himachal Pradesh is known for lakes such as Chandratal and Suraj Tal. D is wrong, because Uttarakhand's lakes include Nainital, Bhimtal and the mysterious Roopkund. Exam tip: Tsomgo (Changu) and Gurudongmar are Sikkim lakes; Pangong Tso and Tso Moriri are in Ladakh.

The correct answer is A, Basavanna. Basavanna led the Virashaiva or Lingayat movement in Karnataka in the twelfth century. He served as a minister at the court of King Bijjala at Kalyana. His followers worship Shiva in the form of a linga, usually worn in a small case on the body, and they questioned caste, rituals and the theory of rebirth, and supported the remarriage of widows. Basavanna and fellow saints such as Allama Prabhu and Akka Mahadevi taught through vachanas, short sayings in simple Kannada, and met in the Anubhava Mantapa to discuss spiritual questions. The other three names all belong to the Tamil country. B is wrong, because Appar was a Tamil Nayanar saint devoted to Shiva, not a leader in Karnataka. C is wrong, because Sambandar was also a Tamil Nayanar, whose hymns are collected in the Tevaram. D is wrong, because Sundarar was another Tamil Nayanar saint. Exam tip: Virashaiva, Basavanna, Kannada vachanas; Nayanars Appar, Sambandar and Sundarar, Tamil Tevaram.

The correct answer is A, Amuktamalyada. Krishnadevaraya wrote this Telugu poem, and a part of it sets out his ideas on how a king should rule. Krishnadevaraya of the Tuluva dynasty ruled Vijayanagara from 1509 to 1529 and was himself a poet, which earned him the title Andhra Bhoja. Amuktamalyada tells the story of Andal, the Tamil woman saint, and her marriage to Lord Vishnu, but history books quote it for its advice on statecraft: a king should rule with an eye to dharma, improve the harbours of his country, encourage trade and look after his subjects. His court had eight Telugu poets known as the Ashtadiggajas. B is wrong, because Jambavati Kalyanam is a Sanskrit drama by him, not a Telugu work on statecraft. C is wrong, because Rayavachakamu is a later Telugu prose account of his reign, written by others. D is wrong, because Satyavadu Parinaya is a Sanskrit work credited to him, not a Telugu text on polity. Exam tip: Krishnadevaraya in Telugu, Amuktamalyada; in Sanskrit, Jambavati Kalyanam.