Defence 2024 Previous Year GK Questions with Answers

The correct answer is C, a mechanism to reduce CO2 emission. A nuclear reactor splits heavy atoms; it burns no fuel, so it releases no carbon dioxide and needs no equipment to cut such emissions. The heat of fission is produced in the reactor core, carried away by a coolant, passed to water in a heat exchanger or steam generator, and the steam then turns a turbine coupled to a generator. Control rods of cadmium or boron absorb spare neutrons and a moderator such as heavy water slows them down so that fission continues steadily. Option A is wrong as a choice because the turbine is the part that actually converts steam energy into electricity. Option B is wrong because the heat exchanger carries heat from the radioactive coolant loop to the clean water loop. Option D is wrong because the reaction chamber, the core holding the fuel rods, is where fission happens. Exam tip: a nuclear plant emits no carbon dioxide; its waste problem is spent radioactive fuel instead.

The correct answer is C, Red blood cells. Mature red blood cells, or erythrocytes, lose their nucleus before they enter the blood. Losing the nucleus, and the mitochondria too, leaves more room for haemoglobin, the iron-rich protein that carries oxygen, and gives the cell its flexible biconcave disc shape, which lets it squeeze through narrow capillaries. With no nucleus, red blood cells cannot divide or repair themselves; they live about 120 days, are made in the red bone marrow and are broken down mainly in the spleen, often called the graveyard of red blood cells. Platelets also lack a nucleus, but they are cell fragments, not whole cells. A is wrong, because muscle cells have nuclei, and skeletal muscle fibres even have many. B is wrong, because phagocytic cells such as neutrophils and macrophages have a nucleus; a neutrophil's nucleus has several lobes. D is wrong, because the ciliated cells lining the windpipe and the oviduct are normal cells with a nucleus. Exam tip: human red blood cells have no nucleus, live 120 days, are born in bone marrow and end in the spleen.

The correct answer is C, Abscisic acid. It is the main growth inhibitor among plant hormones and works against the growth promoters. Abscisic acid, or ABA, is called the stress hormone because it helps plants survive drought, cold and salt: it makes the stomata close to save water, keeps seeds and buds dormant so they do not sprout in bad weather, and helps leaves and fruits to age and fall. So when a question asks which hormone slows or stops growth, ABA is the answer; ethylene is the other hormone linked with ageing and ripening. A is wrong, because auxins promote growth by making cells elongate, and they make shoots bend towards light. B is wrong, because cytokinins promote cell division and delay the ageing of leaves. D is wrong, because gibberellins promote stem elongation, break seed dormancy and are sprayed on grapes to increase their size. Exam tip: the growth promoters are auxin, gibberellin and cytokinin; the inhibitor is abscisic acid, the stress hormone.

The correct answer is D, 1, 2, 3 and 4. All four plans came before the First Five Year Plan started on 1 April 1951. The Bombay Plan of 1944 was prepared by eight industrialists led by J. R. D. Tata and G. D. Birla and favoured state-led heavy industry. The Gandhian Plan of 1944 by Shriman Narayan Agarwal stressed village self-sufficiency, cottage industries and agriculture. The People's Plan of 1945 was drawn up by M. N. Roy for the Indian Federation of Labour and put agriculture and nationalisation first over a ten-year period. The Sarvodaya Plan of January 1950 by Jayaprakash Narayan, inspired by Vinoba Bhave, combined Gandhian ideas with land reform and decentralised planning. Even earlier, M. Visvesvaraya's book Planned Economy for India (1934) and the Congress National Planning Committee of 1938 under Nehru had raised the idea. Options A, B and C are wrong only because each leaves out plans that also existed before 1951. Exam tip: sequence them as Visvesvaraya 1934, Bombay and Gandhian 1944, People's 1945, Sarvodaya 1950, Planning Commission March 1950, First Plan 1951.

The correct answer is C, 14 days. Under Article 109 a Money Bill can be introduced only in the Lok Sabha, and after it is passed there it is sent to the Rajya Sabha, which cannot reject or amend it. The Rajya Sabha must return the Bill within fourteen days, with or without recommendations; the Lok Sabha may accept or reject those recommendations, and if the Bill is not returned within fourteen days it is deemed to have been passed by both Houses in the form the Lok Sabha passed it. Whether a Bill is a Money Bill is decided by the Speaker of the Lok Sabha under Article 110, and the Speaker's certificate is final. The President cannot return a Money Bill for reconsideration. A, 12 days, B, 21 days, and D, 30 days, are not periods laid down anywhere in the Constitution for Money Bills; the 14-day limit is the only one, and the same 14 days applies to a state Legislative Council under Article 198. Exam tip: Money Bill, Article 110 defines it, Article 109 gives the Rajya Sabha 14 days, and the Speaker's decision is final.

The correct answer is B, Tenth Schedule. The Tenth Schedule, popularly called the anti-defection law, was added by the 52nd Constitutional Amendment Act of 1985. It disqualifies a member of Parliament or a state legislature who voluntarily gives up the membership of his party or who votes, or abstains from voting, against the direction of the party whip without permission; an independent member is disqualified if he joins a party. The presiding officer, the Speaker or the Chairman, decides the question, subject to judicial review after the Kihoto Hollohan case of 1992. The 91st Amendment of 2003 removed the protection for a one-third split, and now only a merger backed by two-thirds of a legislature party is allowed. A, the Ninth Schedule, added by the First Amendment of 1951, protects listed laws, mainly on land reform, from court challenge. C, the Eleventh Schedule, lists the 29 subjects of the panchayats under the 73rd Amendment. D, the Sixth Schedule, deals with the administration of tribal areas in Assam, Meghalaya, Tripura and Mizoram. Exam tip: Tenth Schedule means anti-defection, 52nd Amendment of 1985, tightened by the 91st Amendment of 2003.

The correct answer is B, 1 and 3, that is Bihar and Manipur. The Sun is overhead, with its rays vertical at noon, only at places between the Tropic of Cancer (23.5 degrees N) and the Tropic of Capricorn (23.5 degrees S). The Tropic of Cancer crosses India through eight states: Gujarat, Rajasthan, Madhya Pradesh, Chhattisgarh, Jharkhand, West Bengal, Tripura and Mizoram. Any state lying wholly north of this line never gets vertical rays. Bihar stretches roughly from 24.3 to 27.5 degrees N and Manipur from about 23.8 to 25.7 degrees N, so both lie entirely north of the tropic and the Sun is never directly overhead there. A and C are wrong because they include Chhattisgarh, and D is wrong because it includes Rajasthan; the Tropic of Cancer passes through both, so their southern parts do receive vertical rays around 21 June. Exam tip: memorise the eight tropic states, Gujarat, Rajasthan, MP, Chhattisgarh, Jharkhand, West Bengal, Tripura, Mizoram; states such as Bihar, UP, Punjab, Manipur and Assam lie north of the line.

The correct answer is C, At the North Pole. The Coriolis force is the apparent force caused by the rotation of the Earth that deflects moving air and water to the right in the northern hemisphere and to the left in the southern hemisphere. Its size is proportional to the sine of the latitude, so it is zero at the equator, where the sine of 0 degrees is zero, and greatest at the poles, where the sine of 90 degrees is one. This is why tropical cyclones cannot form within about 5 degrees of the equator, and why winds around a low-pressure system circle anticlockwise in the northern hemisphere and clockwise in the southern. It was described by the French scientist Gaspard-Gustave de Coriolis in 1835. A, At the Equator, the effect is zero, not largest. B, At the tropics, at 23.5 degrees, the effect is small. D, At 45 degrees latitude, the effect is only about 71 percent of its value at the poles. Exam tip: the Coriolis force is zero at the equator and maximum at the poles, and it grows with the speed of the moving body.

The correct answer is D, Indo-Greeks. The Indo-Greek kings who ruled the north-west of India from about the second century BCE were the first in Indian history to issue coins that carried the name and portrait of the ruler, with Greek legends on one side and Prakrit in the Kharoshthi script on the other. The coins of Menander (Milinda), who appears in the Buddhist text Milindapanho, are the best known. This practice of putting the ruler's head and name on coins was later followed by the Kushanas and the Guptas. These coins are also the main source for the names of more than thirty Indo-Greek kings, most of whom are known from nothing else. A, the Mauryas, used punch-marked silver coins with symbols but no names or portraits. B, the Pushyabhutis of Thanesar and Kanauj, the dynasty of Harsha, came much later, in the sixth and seventh centuries CE. C, the Guptas, issued beautiful gold dinars with royal portraits, but they followed the Indo-Greek and Kushana example. Exam tip: first coins with rulers' names and images, Indo-Greeks; first large gold coinage, Kushanas; punch-marked coins, Mauryas.

The correct answer is C, Gandhar. Buddhist texts list sixteen mahajanapadas of the sixth century BCE, and Gandhara, in the north-west covering the Peshawar and Rawalpindi region, had its capital at Taxila (Takshashila), near present-day Islamabad in Pakistan. Taxila stood on the Uttarapatha trade route and grew into a famous centre of learning linked in tradition with Panini, Chanakya and the physician Jivaka. Its ruins are a UNESCO World Heritage Site. Gandhara later became famous for the Gandhara school of art under the Kushanas. A, Kuru, had its capital at Indraprastha, near Delhi, with Hastinapur as another centre. B, Kasi, had Varanasi as its capital. D, Avanti, in Malwa, had Ujjain as its capital, with Mahishmati in the south. Exam tip: learn them in pairs, Gandhara with Taxila, Avanti with Ujjain, Kosala with Shravasti, Vatsa with Kaushambi, and Magadha with Rajgir and later Pataliputra.

The correct answer is D, Bowman's capsule. Each human kidney has about one million nephrons, and every nephron begins with a cup-shaped Bowman's capsule that encloses a knot of capillaries called the glomerulus. Blood enters the glomerulus under pressure, and water, salts, glucose, urea and other small molecules are pushed out through its walls into the capsule; this is ultrafiltration, the first step of urine formation. Proteins and blood cells are too large to pass and stay in the blood. The filtrate then flows through the tubule, where useful substances such as glucose and most of the water are reabsorbed. A, the Collecting duct, only gathers urine from many nephrons and carries it to the pelvis of the kidney. B, the Renal vein, carries filtered blood away from the kidney and is not part of a nephron. C, the Ureter, is the tube that takes urine from the kidney to the bladder. Exam tip: Bowman's capsule plus glomerulus is the Malpighian body, the filter of the nephron.

The correct answer is C, Rickets. Vitamin D helps the intestine absorb calcium and phosphorus, so without it the bones of a growing child stay soft and bend, giving bow legs, a pigeon chest and a large forehead; this disease is rickets. In adults the same deficiency causes osteomalacia, a softening of already formed bones. Vitamin D is called the sunshine vitamin because the skin makes it when sunlight falls on it; fish liver oil, egg yolk and milk are food sources. Its chemical name is calciferol. A, Beriberi, is caused by lack of vitamin B1 (thiamine) and affects the nerves and the heart. B, Scurvy, comes from lack of vitamin C (ascorbic acid) and causes bleeding gums. D, Pneumonia, is an infection of the lungs caused by bacteria or viruses, not a deficiency disease. Exam tip: remember the pairs, A night blindness, B1 beriberi, C scurvy, D rickets, K delayed clotting.

The correct answer is D, General theory of relativity. LIGO, the Laser Interferometer Gravitational-Wave Observatory in the USA, detected gravitational waves for the first time in September 2015 (announced in February 2016), and such waves were predicted by Einstein's general theory of relativity in 1916. General relativity treats gravity as the curving of space-time and says that huge accelerating masses, like two black holes spiralling into each other, send ripples through space-time at the speed of light. LIGO's two detectors at Hanford and Livingston measured a change in arm length smaller than the width of a proton. India is building a third detector, LIGO-India, at Hingoli in Maharashtra. A, String theory, has made no prediction that any experiment has yet confirmed. B, Special relativity, deals with motion at constant speed and does not include gravity. C, Quantum mechanics, describes atoms and particles, not gravitational waves. Exam tip: LIGO means gravitational waves, which means general relativity; the 2017 Physics Nobel went to Weiss, Barish and Thorne for it.

The correct answer is D, Magnesium hydroxide. Milk of magnesia is a white suspension of magnesium hydroxide, Mg(OH)2, in water, and its milky look gives it the name. It is a mild base, so it is taken as an antacid to neutralise excess hydrochloric acid in the stomach and relieve acidity; in larger doses it works as a laxative. Being only slightly soluble, it does not make the stomach strongly alkaline, which is why it is safe as a medicine. A, Magnesium bicarbonate, exists only in solution and is not used as a medicine. B, Magnesium carbonate, is used in chalk and as a drying powder for the hands in sports, and is not called milk of magnesia. C, Magnesium sulphate, is Epsom salt, used in bath salts and as a purgative. Exam tip: pair the common names: milk of magnesia is Mg(OH)2, Epsom salt is MgSO4.7H2O, milk of lime is a Ca(OH)2 suspension.