NDA 2022 Previous Year GK Questions with Answers

The correct answer is A, Cell will lose water. A medium that holds less water than the cell is a hypertonic medium, so water moves out of the cell by osmosis and the cell shrinks. Osmosis is the movement of water through a semi-permeable membrane from the side where water is in higher concentration to the side where it is lower. In an animal cell this loss of water makes the cell shrivel, and the matching change in a plant cell is called plasmolysis, where the protoplasm pulls away from the cell wall. In a hypotonic medium the opposite happens and the cell swells, which is why red blood cells burst in pure water, while in an isotonic medium there is no net movement at all. B is wrong because water always moves when the two concentrations differ. C and D are wrong because gaining water and swelling happen in a hypotonic medium and not in a hypertonic one. Exam tip: hypertonic means water out and shrinking, hypotonic means water in and swelling.

The correct answer is D, Colourless. Hydrogen is a colourless, odourless and tasteless gas, so none of the colours listed fits it. It is the lightest element, with one proton and one electron, and it is the most abundant element in the universe, although on the earth it is found mostly combined in water and in organic compounds. Hydrogen exists as the diatomic molecule H2, burns in air with a pale blue flame and gives only water as the product, which is why it is studied as a clean fuel. It is used to make ammonia by the Haber process and to harden vegetable oils into vanaspati. A is wrong because no common form of hydrogen is yellow. B is wrong because orange is the colour seen in sodium vapour lamps and not in hydrogen. C is wrong because none of the gases here is black; carbon in its soot form is black, but that is a solid. Exam tip: hydrogen, oxygen and nitrogen are all colourless and odourless gases.

The correct answer is C, 2 s. A simple pendulum about one metre long completes one full swing in roughly two seconds, and a pendulum of this length is called the seconds pendulum. The time period of a simple pendulum is T = 2 pi times the square root of L divided by g, where L is the length of the thread and g is the acceleration due to gravity, about 9.8 metres per second squared. Putting L = 1 metre gives T = 2 x 3.14 x the square root of 1 divided by 9.8, which comes to about 2.01 seconds. The period depends only on the length and on g, not on the mass of the bob or on how far it is pulled aside, so long as the swing is small. A is wrong because a 6 second period needs a thread about 9 metres long. B is wrong because a 4 second period needs a thread about 4 metres long. D is wrong because a 1 second period belongs to a thread of only about 25 centimetres. Exam tip: the period doubles only when the length becomes four times.

The correct answer is D, Ghana. Kwame Nkrumah led Ghana and was one of the five founders of the Non-Aligned Movement. He took Ghana to independence in 1957, the first country in sub-Saharan Africa to break free of colonial rule, and served first as its Prime Minister and then as its President. The Non-Aligned Movement was built by five leaders, Jawaharlal Nehru of India, Gamal Abdel Nasser of Egypt, Josip Broz Tito of Yugoslavia, Sukarno of Indonesia and Nkrumah of Ghana, who refused to join either the American or the Soviet bloc during the Cold War. Their effort led to the first NAM summit at Belgrade in 1961. A is wrong because Nigeria became independent in 1960 and its early leader was Abubakar Tafawa Balewa. B is wrong because Kenya was led to freedom by Jomo Kenyatta. C is wrong because the first Prime Minister of Uganda was Milton Obote. Exam tip: remember the five founders of NAM and the Belgrade summit of 1961.

The correct answer is A, Bryophytes. Bryophytes live on land but still need water to complete reproduction, so they are called the amphibians of the plant kingdom. Mosses, liverworts and hornworts belong here. They grow in damp, shady places, have no true roots, stems or leaves and no vascular tissue, so water moves through them by simple absorption. Their male gametes swim to the egg through a film of water, which ties them to moist ground exactly as frogs are tied to ponds. Option B is wrong because thallophytes are the algae, mostly water plants that never left water. Option C is wrong because pteridophytes, the ferns, are the first plants with true vascular tissue, xylem and phloem. Option D is wrong because gymnosperms such as pine and cycas bear naked seeds and use pollen, not swimming gametes. Exam tip: bryophytes are amphibians of the plant kingdom, pteridophytes are the first vascular plants, and gymnosperms are the first seed plants.

The correct answer is D, 2 s. Convert the units first: 1 kilohertz is 1000 hertz and 50 centimetres is 0.5 metre. The speed is frequency multiplied by wavelength, that is 1000 multiplied by 0.5, which gives 500 metres per second. Time equals distance divided by speed, so 1000 metres divided by 500 metres per second gives 2 seconds.

Option A, 5 s, would follow from using a speed of 200 metres per second. Option B, 4 s, corresponds to a speed of 250 metres per second, which arises if the wavelength is halved by mistake. Option C, 3 s, is close to the time sound actually takes to cover a kilometre in ordinary air, about 340 metres per second, and is the trap for candidates who use the remembered speed of sound instead of the speed calculated from the data given.

The correct answer is A, the Bombay Plan. The Bombay Plan of 1944 was drawn up by a group of eight, mostly leading industrialists such as J. R. D. Tata, G. D. Birla, Purushottamdas Thakurdas, Lala Shri Ram and Kasturbhai Lalbhai, with John Mathai among them. It proposed a fifteen-year plan to double per-capita income and treble national income, with the state taking the lead in heavy industry and infrastructure and the private sector working under its guidance. It showed that even big business wanted the state to plan the economy and to run a large public sector, and this consensus shaped the Planning Commission of 1950 and the mixed-economy model. B, the demand of peasants, and C, the demand of workers' unions, were not the origin of the planning idea; they were groups the plans tried to serve. D, the Gandhian vision, favoured village industries and decentralisation and was set out separately in the Gandhian Plan of 1944 by S. N. Agarwal. Exam tip: Bombay Plan 1944 by eight industrialists; People's Plan 1945 by M. N. Roy; Gandhian Plan 1944 by S. N. Agarwal.

The correct answer is A, precipitation. Precipitation is any form of water, liquid or solid, that falls from clouds to the ground. When the temperature is above freezing it falls as rain or drizzle; below freezing, water vapour turns directly into ice crystals that fall as snow. Sleet is rain that freezes into small ice pellets while falling through a cold layer of air, and hail is made of hard ice balls built up layer by layer inside towering cumulonimbus clouds during thunderstorms. All three are therefore solid forms of precipitation. B, Condensation, is the change of water vapour into tiny droplets or ice crystals, which forms clouds, dew, frost and fog, but these do not fall from clouds. C, Transpiration, is the loss of water vapour from the leaves of plants. D, Evaporation, is the change of liquid water into vapour, the first step of the water cycle. Exam tip: rain, drizzle, snow, sleet and hail fall, so they are precipitation; dew, frost, fog and mist form on or near the ground, so they are condensation.

The correct answer is C, refraction of starlight. Starlight has to cross many layers of air before it reaches the eye, and these layers keep changing in temperature and density, so their refractive index keeps changing too. The light is bent a little differently every moment, the apparent position of the star shifts slightly and the amount of light entering the eye rises and falls. This flickering is what we call twinkling. A star is so far away that it acts as a point source, so the small shifts are easily seen. Planets are nearer and appear as tiny discs; light from the many points of the disc averages out, so planets do not twinkle. A, Diffraction, is the bending of light around edges and is not the cause. B, Reflection, sends light back from a surface and cannot make a star flicker. D, Scattering, of sunlight by air makes the sky blue but does not cause twinkling. Exam tip: twinkling and the early sunrise both come from atmospheric refraction; the blue sky and the red sunset come from scattering.