200 questions · 180 minutes · −0.25 per wrong answer · Free
Answer: (B) weight
The poundal is the absolute unit of force in the FPS system (the force that gives 1 lb an acceleration of 1 ft/s²). Weight is a force, so of the options given it is the quantity measured in poundals. Mass is measured in pounds, momentum in lb·ft/s and energy in foot-poundals, so A, C and D are wrong.
Answer: (B) M S Swaminathan
M S Swaminathan led the introduction of high-yielding wheat and rice varieties in the 1960s and is called the Father of the Green Revolution in India. Verghese Kurien is linked with the White Revolution (milk), Dhyan Chand with hockey and Vikram Sarabhai with the space programme.
Answer: (D) Lactose
Lactose (milk sugar) is a disaccharide made of one glucose and one galactose unit. Glucose and fructose are hexose monosaccharides and ribose is a pentose monosaccharide, so A, B and C are all monosaccharides.
Answer: (A) David Butler
The British political scientist David Butler pioneered the systematic study of elections (psephology) and is called the father of election science. T. N. Seshan is remembered for electoral reforms as Chief Election Commissioner, and Sukumar Sen was India's first Chief Election Commissioner, but neither founded the discipline.
Answer: (A) shortsightedness
If the eye lens becomes too strongly converging (higher power), distant objects are focused in front of the retina, which is myopia or shortsightedness. Longsightedness is caused by too little converging power, astigmatism by an unevenly curved cornea, and colour blindness by defective cone cells.
Answer: (A) Steel
Steel has high retentivity and high coercivity, so once magnetised it keeps its magnetism, which is what a permanent magnet needs. Soft iron loses its magnetism easily and is used for electromagnets, copper is not ferromagnetic, and nickel is only weakly suited compared with steel.
Answer: (C) both (A) and (B)
A moving charge (an electric current) produces a magnetic field, and by Maxwell's displacement-current idea a changing electric field also produces one. Since both sources work, the answer is (C); choosing only (A) or (B) leaves out the other.
Answer: (D) Black
The sky looks blue from the ground because air molecules scatter blue sunlight towards us. In outer space there is no atmosphere to scatter light, so the sky appears black. Red, blue and indigo would all require scattering by air.
Answer: (A) Patna
The National Inland Navigation Institute, set up by the Inland Waterways Authority of India to train inland-vessel crews, is at Gaighat in Patna, Bihar, on National Waterway 1 (the Ganga). Balasore, Bangalore and Dehradun do not host it.
Answer: (B) SYNCOM-3
Syncom 3, launched by NASA in August 1964, was the first geostationary satellite and relayed TV coverage of the 1964 Tokyo Olympics. Anik (1972) and Westar (1974) came later, and Molniya satellites used highly elliptical, not geostationary, orbits.
Answer: (C) free delocalized electrons.
In graphite each carbon uses three electrons for bonds within its layer, and the fourth electron is delocalised across the layer, free to carry current. A tetrahedral arrangement describes diamond, which does not conduct, and localised bonds or electrostatic bonding do not supply mobile charge carriers.
Answer: (B) 1972
The National Committee on Environmental Planning and Coordination (NCEPC) was set up in 1972, the year of the Stockholm Conference, as India's first apex environmental body. It was later succeeded by the Department of Environment (1980), so 1980 is the wrong date, as are 1970 and 1974.
Answer: (A) Starch
Starch is a natural polymer of glucose made by plants. Teflon, neoprene and nylon are all synthetic polymers made in factories, so B, C and D are wrong.
Answer: (D) 60
The best-known fullerene, buckminsterfullerene, is $C_{60}$, a cage of 60 carbon atoms arranged like a football. The other numbers do not describe this molecule.
Answer: (B) Lindemann
Raymond Lindeman (1942) proposed the ten per cent law: only about 10% of the energy at one trophic level passes to the next. Odum is known for ecosystem ecology generally, Tansley coined the term 'ecosystem', and Darwin proposed natural selection.
Answer: (B) Dubai
COP 28, the 28th UN climate change conference, was held at Expo City, Dubai, UAE, from 30 November to 12 December 2023. India, the USA and Japan were not hosts.
Answer: (B) Cyanobacteria
Cyanobacteria (blue-green algae) reproduce only asexually, by fission, fragmentation or spores, and no sexual process is known in them. Fungi and algae have clear sexual cycles, and bacteria show genetic recombination by conjugation, often described as a primitive sexual process, so A, C and D are not the intended answer.
Answer: (B) 22nd April
Earth Day has been observed on 22 April every year since 1970. 20 March is the International Day of Happiness and 28 February is National Science Day in India, so the other dates are wrong.
Answer: (A) Turtles
Gahirmatha Marine Sanctuary on the Odisha coast protects one of the world's largest mass-nesting (arribada) sites of Olive Ridley sea turtles. Crocodiles are protected at nearby Bhitarkanika, and elephants and deer are not the sanctuary's purpose.
No option is correct as printed — this question is disputed. WBPSC awarded the mark to all candidates: two options (B) 380–750 nm and (C) 390–700 nm are both standard textbook ranges for the visible spectrum.
The question has more than one defensible answer: the limits of visible light are quoted variously as about 380–750 nm and about 390–700 nm (roughly 400–700 nm), so both (B) and (C) appear in standard books. The PSC therefore awarded the mark to all candidates.
Answer: (C) 17
The 2030 Agenda adopted by the UN in 2015 contains 17 Sustainable Development Goals with 169 targets. The earlier Millennium Development Goals numbered 8, and 15, 16 or 18 do not match the SDGs.
Answer: (C) Acid Rain
'Stone cancer' is the corrosion and pitting of marble and limestone monuments, such as the Taj Mahal, by acid rain: sulphuric acid reacts with calcium carbonate. SPM causes yellowing or blackening rather than this decay, and frost or VOCs are not the cause named by the term.
Answer: (A) Johannesberg
The World Summit on Sustainable Development (WSSD, 'Rio+10') was held in Johannesburg, South Africa, in 2002. Brazil hosted the 1992 Earth Summit and Rio+20, not the WSSD, and Paris hosted COP 21.
Answer: (B) Mercury
Minamata disease, first seen in Minamata, Japan, is methylmercury poisoning from eating contaminated fish. Cadmium causes itai-itai disease, arsenic causes arsenicosis (blackfoot disease), and lead causes plumbism.
Answer: (C) New Delhi
The Central Pollution Control Board, set up in 1974 under the Water Act, has its headquarters in New Delhi. Kolkata, Bangalore and Mumbai host only zonal or regional offices.
No option is correct as printed — this question is disputed. WBPSC awarded the mark to all candidates: the 'first film theatre of India' is not clearly any listed person's work (usually credited to J. F. Madan, not an option), so the question has no clear correct option.
The question has no single settled answer among the options. The Lumière Brothers only held the first film show in India (Watson's Hotel, Bombay, 1896) and did not build a theatre, Dadasaheb Phalke made the first Indian feature film, and Dhirendra Nath Ganguly was an early Bengali filmmaker; the first permanent cinema hall is usually credited to J. F. Madan's Elphinstone Picture Palace in Calcutta (1907). The Commission therefore awarded the mark to all candidates.
Answer: (B) acetic acid
Vinegar is about 5–8% acetic (ethanoic) acid in water, made by bacterial oxidation of ethyl alcohol. Ethyl alcohol is the starting material, not vinegar itself; formic acid occurs in ant stings, and vanadium is a metal.
Answer: (B) Vaishali
Vajji (Vrijji), a confederacy of clans led by the Licchavis, had its capital at Vaishali in north Bihar. Kushinara and Pava were the centres of the Mallas, and Shuktimati was the capital of Chedi.
Answer: (A) decreased
In an adiabatic process no heat enters or leaves, so by the first law $\Delta U = -W$. During expansion the gas does work on its surroundings, so its internal energy falls and it cools. It cannot increase or stay the same, and 'dissipated' is not the right description.
Answer: (D) live microbial food supplement
Probiotics are live beneficial micro-organisms, such as Lactobacillus in curd, taken as food or supplements to improve gut health. They are not antibiotics (which kill bacteria), nor allergens or cancer-causing microbes.
Answer: (D) Thermosphere
In the thermosphere, absorption of high-energy solar radiation raises temperatures to well over 1000 °C, so it is called the hot layer. Temperature falls with height in the troposphere and mesosphere, and the stratosphere warms only moderately because of ozone.
Answer: (B) Norway
The Svalbard Global Seed Vault, opened in 2008, is dug into a mountain on Spitsbergen in Norway's Svalbard archipelago. Switzerland, Finland and Denmark do not host it.
Answer: (C) Gallium
Gallium is a metal (it melts in the hand at about 30 °C). Boron, silicon and germanium have properties between metals and non-metals and are classed as metalloids.
Answer: (B) April 26
World Intellectual Property Day is observed on 26 April, the date in 1970 when the convention establishing WIPO came into force. The other April dates are not linked to it.
Answer: (B) Bacteria
Denitrification, the conversion of soil nitrates back to nitrogen gas, is carried out by bacteria such as Pseudomonas and Thiobacillus denitrificans. Fungi, algae and protozoa do not perform this step of the nitrogen cycle.
Answer: (D) Kerala
The Silent Valley Movement (1970s–80s) stopped a hydroelectric dam on the Kunthipuzha river in Palakkad district, Kerala, saving its evergreen forest, now Silent Valley National Park. It did not take place in the other states.
Answer: (B) Current density
Current density $\vec{J}$ (current per unit area) has a direction at each point and is a vector. Electric current, though it has a sense of flow, does not obey vector addition and is a scalar; power and wattless current are also scalars.
Answer: (A) New york
The United Nations Development Programme has its headquarters in New York. Geneva hosts bodies such as the WHO and WTO, Paris hosts UNESCO, and London hosts the IMO.
Answer: (B) 18
Answer as of 2023 — this may have changed since.
As of 2023 India had 18 notified biosphere reserves, from Nilgiri (1986, the first) to Panna (2011), of which 12 are in UNESCO's World Network. 17, 19 and 20 do not match the count for that year.
Answer: (A) Abdominal region
The five lumbar vertebrae form the lower back, behind the abdomen, between the thoracic vertebrae above and the sacrum below. Thoracic vertebrae are in the chest, cervical vertebrae in the neck, and the sacrum and coccyx in the hip region.
Answer: (D) SF$_6$
Sulphur hexafluoride has a 100-year global warming potential of about 23,500 times that of CO$_2$, the highest of any gas assessed by the IPCC. CFCs have GWPs in the thousands, while CO$_2$ is the reference value of 1.
Answer: (A) SO$_2$
Lichens absorb water and gases directly through their surface and are killed by even low levels of sulphur dioxide, so they are used as indicators of SO$_2$ pollution. CO$_2$ and N$_2$ are normal air components, and CO is not what lichens indicate.
Answer: (B) 1948
The World Health Organization's constitution came into force on 7 April 1948, which is why that date is World Health Day. The other years do not match.
Answer: (C) Copper
In a metal such as copper, resistance rises with temperature because the vibrating lattice scatters electrons more, giving a positive temperature coefficient. Carbon and the semiconductor germanium have negative coefficients, and electrolytes conduct better when warmed.
Answer: (C) Both
Chlorine is the standard disinfectant for public water supplies, and potassium permanganate is widely used to disinfect well water in rural areas. Since both are used, (C) is correct; NO$_2$ is a pollutant, not a disinfectant.
Answer: (A) Arthur Ashe Stadium
Answer as of 2023 — this may have changed since.
Arthur Ashe Stadium at Flushing Meadows, New York, home of the US Open, seats about 23,000 and is the largest tennis-specific stadium. The O2 Arena, Rotterdam Ahoy and Perth Arena are multi-purpose indoor arenas with smaller tennis capacity.
Answer: (C) Sewage
Biochemical oxygen demand measures how much oxygen microbes need to decompose organic matter, so adding organic sewage raises BOD sharply. Heavy metals are toxic but not biodegradable organic load, and plankton are not the main driver named here.
Answer: (A) 1947
The General Agreement on Tariffs and Trade was signed by 23 countries in Geneva in October 1947. It came into force on 1 January 1948, which makes 1948 the tempting wrong option; 1954 and 1960 are unrelated.
Answer: (C) Mesosphere
Temperature falls with height through the mesosphere to about −90 °C at the mesopause, the coldest part of the atmosphere. The thermosphere above is the hottest layer, and the troposphere and stratosphere are never that cold.
Answer: (B) Odisha
Taptapani, known for its sulphur hot springs, is in Ganjam district of Odisha. It is not in Uttar Pradesh, Madhya Pradesh or Jharkhand.
Answer: (A) Lung
SARS-CoV-2 enters cells through ACE2 receptors that are abundant in the respiratory tract, so COVID-19 primarily attacks the lungs, causing pneumonia in severe cases. Liver, kidney and spleen can be affected secondarily but are not the primary target.
Answer: (C) 1 to 100
Nanoparticles are conventionally defined as particles with at least one dimension between 1 and 100 nanometres. 100–1000 nm is the sub-micron range, and 0.1–10 nm or 0.01–1 nm reach down to atomic sizes.
Answer: (C) Spain
Pablo Picasso, co-founder of Cubism, was born in Málaga, Spain, in 1881. He spent much of his working life in France, which makes (B) the tempting wrong option, but he was Spanish.
Answer: (D) Japan
Minamata Bay is in Kumamoto Prefecture on Kyushu, Japan, where mercury waste from the Chisso factory caused Minamata disease. It is not in Korea or China.
Answer: (C) 2f
Kinetic energy depends on $v^2$, and $\sin^2\omega t = \frac{1 - \cos 2\omega t}{2}$, so the kinetic and potential energies oscillate at twice the pendulum's frequency, 2f. Kinetic energy peaks twice per oscillation (once each way through the mean position), so f or f/2 is wrong.
Answer: (C) The Elephant Whisperers
Kartiki Gonsalves's The Elephant Whisperers, produced by Guneet Monga, won Best Documentary Short at the 2023 Oscars, the first Indian production to win in a documentary category. All That Breathes was nominated for Best Documentary Feature but did not win, and the other two are non-Indian nominees.
Answer: (B) Lenz's Law.
Lenz's law states that the induced e.m.f. acts in a direction that opposes the change in flux causing it, so it gives the direction. Faraday's law gives the magnitude of the induced e.m.f., and Ampere's and Maxwell's laws relate currents and fields.
Answer: (B) Pierre de Coubertin
French educator Baron Pierre de Coubertin founded the International Olympic Committee in 1894 and revived the Games at Athens in 1896. Spyridon Samaras composed the Olympic Hymn, and Wilson and Hoover were US Presidents.
Answer: (B) s < p < d < f
Within one shell of a many-electron atom, orbitals with higher azimuthal quantum number l penetrate less towards the nucleus, so energy rises in the order s < p < d < f within a shell. The other orders put higher-l orbitals below lower-l ones, which is wrong.
Answer: (A) 2000 nm.
Escherichia coli is a rod about 2 µm long and 0.5 µm wide, and 2 µm is 2000 nm. 200 nm and 20 nm are the size range of viruses, and 2 nm is about the width of DNA.
Answer: (A) 8
Answer as of 2023 — this may have changed since.
North Bengal has eight districts: Darjeeling, Kalimpong, Jalpaiguri, Alipurduar, Cooch Behar, Uttar Dinajpur, Dakshin Dinajpur and Malda. Kalimpong and Alipurduar were carved out in the 2010s, so older counts of 6 or 7 are out of date.
Answer: (B) Pratham
The 2021 Indira Gandhi Prize for Peace, Disarmament and Development was given to Pratham, the education NGO known for its ASER reports on children's learning. The other organisations were not that year's winners.
No option is correct as printed — this question is disputed. WBPSC awarded the mark to all candidates: two correct options — Mg (C) is part of chlorophyll and Fe (B) is required for its synthesis.
Magnesium is the central atom of the chlorophyll molecule, but iron is also essential for chlorophyll synthesis (its deficiency causes chlorosis even though Fe is not part of the molecule). With both (B) and (C) defensible, the Commission awarded the mark to all candidates.
Answer: (C) Kollam beach
Kollam beach in Kerala is officially also called Mahatma Gandhi Beach. Marari beach is near Alappuzha, Cherai beach is near Kochi, and Kannur has Payyambalam beach, none of which carries that name.
Answer: (B) Gause
G. F. Gause (1934) showed with Paramecium cultures that two species competing for the same limiting resource cannot coexist indefinitely, which is the competitive exclusion (Gause's) principle. Darwin and Lamarck proposed theories of evolution, and Odum is known for ecosystem ecology.
Answer: (B) increases
Charge of either sign spreads over the bubble's surface, and the like charges repel each other, producing an outward electrostatic pressure. This adds to the gas pressure inside, so the bubble expands and its radius increases; the sign of the charge does not matter.
Answer: (A) Brine
Brine is a solution of common salt in water, so evaporating it leaves solid salt behind. Bromine, mercury and alcohol are pure liquids that simply vaporise completely.
Answer: (A) CF$_4$
CF$_4$ is tetrahedral, with all F–C–F angles 109.5°. PF$_5$ is trigonal bipyramidal (axial–equatorial angles of 90°), and SF$_6$ and SiF$_6^{2-}$ are octahedral with 90° angles.
Answer: (A) Angular acceleration
The rotational form of Newton's second law is $\tau = I\alpha$, so a constant torque produces a constant angular acceleration. Angular velocity and displacement then change over time as a result, and linear acceleration needs a net force rather than a torque.
Answer: (D) accelerating protons
A cyclotron uses a magnetic field and an alternating electric field between two 'dees' to accelerate heavy positive particles such as protons and deuterons. It is unsuitable for electrons, whose mass rises quickly with speed and throws them out of step, and it does not measure charge or voltage.
Answer: (A) Black
Copper(II) sulphide precipitates as a black solid when H$_2$S is passed through a copper salt solution, a standard test in group II analysis. Blue is the colour of hydrated copper sulphate (CuSO$_4$), and yellow sulphides are those of cadmium or arsenic.
Answer: (C) 5
A diatomic molecule like H$_2$ has 3 translational and 2 rotational degrees of freedom at ordinary temperatures, totalling 5. Three applies to a monatomic gas, and 6 would count rotation about the bond axis or vibration, which are not active.
Answer: (C) Dada Saheb Phalke
Dadasaheb Phalke made Raja Harishchandra (1913), India's first full-length, fully indigenous silent feature film. The Lumière Brothers only screened foreign films in Bombay in 1896, and Dhirendra Nath Ganguly's films came later.
Answer: (A) Nandini Gupta
Nandini Gupta from Kota, Rajasthan, won Femina Miss India 2023 at Imphal. Shreya Poonja was the first runner-up and Strela Luwang the second runner-up.
Answer: (B) Uttarakhand
The Valley of Flowers National Park, a UNESCO World Heritage Site, is in Chamoli district of Uttarakhand. It was part of Uttar Pradesh before Uttarakhand was formed in 2000, which makes (A) the tempting wrong option.
Answer: (B) Electronic
Ultraviolet and visible photons have enough energy to move electrons between molecular orbitals, so UV spectroscopy studies electronic transitions. Rotational transitions are studied with microwaves, vibrational ones with infrared, and nuclear spin transitions with radio waves in NMR.
Answer: (D) Gauri
Kavitha Lankesh's 'Gauri', a documentary on the murdered journalist Gauri Lankesh, won the Best Long Documentary award at the South Asian Film Festival of Montreal in 2023. The other titles were not that award's winner.
Answer: (A) Pather Panchali
In FIPRESCI-India's 2022 poll of critics, Satyajit Ray's Pather Panchali (1955) was voted the best Indian film of all time. Ankur, Anand and Mughal-e-Azam are celebrated films but did not top that poll.
Answer: (C) 5000
The Sun's visible surface (photosphere) is at about 5,800 K while Earth's surface averages about 288 K, so the Sun is hotter by more than 5000 kelvin. 1000 K and 500 K understate the gap, and 1,00,000 K is far above the surface temperature.
Answer: (A) World Bank
The Country Partnership Framework is the World Bank Group's multi-year plan for its lending and support to a member country, as in the India CPF. The IMF uses programmes and Article IV reviews, the ADB uses a Country Partnership Strategy, and the WEF is not a lender.
Answer: (A) reduction of lead.
In PbO + H$_2$ → Pb + H$_2$O, hydrogen removes oxygen from lead oxide, so lead is reduced from +2 to metallic lead while hydrogen is oxidised. No chlorine is present to form PbCl$_2$, and PbO is the reactant, not the product.
Answer: (B) Coffee
Liberica excelsa (Coffea liberica var. dewevrei) is a coffee variety, in the news as a climate-resilient alternative to Arabica. It has nothing to do with tea, rice or wheat.
Answer: (B) 2011
The Fukushima Daiichi nuclear disaster followed the earthquake and tsunami of 11 March 2011 in Japan. The other years are wrong.
Answer: (D) 1943
Subhas Chandra Bose took over the Indian Independence League and the INA from Rash Behari Bose in Singapore in July 1943, becoming its Supreme Commander, and formed the Azad Hind government that October. 1945 is when the INA surrendered, and 1932 and 1935 predate the INA.
Answer: (B) 14 July, 2023
Chandrayaan-3 was launched from Sriharikota on 14 July 2023 aboard LVM3-M4, and its lander touched down near the lunar south pole on 23 August 2023. The other dates are wrong.
Answer: (B) larynx
The vocal cords are folds of tissue inside the larynx (voice box). The glottis is only the opening between the cords, the pharynx is the throat cavity above, and the bronchi lie below in the chest.
Answer: (A) Stoichiometry
Stoichiometry, the calculation of quantities in compounds and reactions, rests on the law of definite proportions: a compound always contains its elements in a fixed ratio by mass. Electrometry, photometry and spectrometry are measurement techniques, not branches based on this law.
Answer: (D) Fatty acid and glycerol
A triglyceride is one glycerol esterified with three fatty acids, so lipase digestion releases both fatty acids and glycerol. Options (A) and (C) give only half the products, and amino acids come from proteins.
Answer: (A) Sea
Ocean Thermal Energy Conversion uses the temperature difference between warm surface sea water and cold deep sea water to run a heat engine. It needs a gap of about 20 °C over great depth, which only the tropical ocean provides, not rivers, lakes or wetlands.
Answer: (A) Godavari
The Jayakwadi dam at Paithan in Aurangabad district, Maharashtra, is built on the Godavari, and its hydro-electric unit was set up with Japanese assistance. The Narmada, Cauvery and Ganga do not flow through Paithan.
Answer: (B) 4 GHz
C-band satellite links use about 6 GHz for the uplink and about 4 GHz for the downlink. 14 GHz and 11 GHz are the Ku-band uplink and downlink, and 2 GHz is S-band.
Answer: (B) Toyota
Answer as of 2023 — this may have changed since.
Toyota sold about 10.5 million vehicles in 2022 and stayed the world's top-selling car-maker for the third year in a row, ahead of the Volkswagen Group. Skoda is a Volkswagen brand with far smaller sales.
Answer: (C) Cyano bacteria
In flooded paddy fields, free-living and symbiotic cyanobacteria such as Anabaena, Nostoc and Tolypothrix fix atmospheric nitrogen and serve as biofertiliser. The fern Azolla helps only because of the cyanobacterium Anabaena living in it, so (B) is not the fixer itself.
Answer: (A) Simplex
In broadcast TV, signals flow only from the station to the viewer, which is simplex (one-way) transmission. Half-duplex (walkie-talkie) and full-duplex (telephone) both allow two-way communication.
Answer: (A) Ravi Kannan
Oncologist Dr R. Ravi Kannan, director of the Cachar Cancer Hospital in Silchar, Assam, was the Indian winner of the 2023 Ramon Magsaysay Award. Kailash Satyarthi won the Nobel Peace Prize in 2014, and Adani and Alagh are business figures.
Answer: (C) neutral.
In an n-type semiconductor each free electron from a donor atom leaves behind a positively charged donor ion, so the crystal as a whole stays electrically neutral. Having electrons as majority carriers does not make it negatively charged.
Answer: (B) 11 million Swedish crowns
Answer as of 2023 — this may have changed since.
The Nobel Foundation raised the prize for 2023 by 1 million to 11 million Swedish kronor per prize. The other amounts are wrong.
Answer: (A) 7.5 – 8.5
Sea water is mildly alkaline because of dissolved carbonates and bicarbonates, with pH usually between about 7.5 and 8.5 (surface average about 8.1). Values of 9.5 and above would be strongly alkaline.
Answer: (C) Both
Peroxyacetyl nitrate, a component of photochemical smog, is a strong eye irritant, and it is also listed as a mutagen linked to skin cancer. Since both effects are attributed to it, (C) is the answer; liver cancer is not a recognised PAN effect.
Answer: (B) Indoor Air pollution
An electrostatic precipitator charges dust particles in air passed through it and collects them on plates, so it can only clean air drawn through an enclosed unit, as in electronic indoor air cleaners. It does not treat water or remove odorous gases. Note: the best-known use of electrostatic precipitators is in power-plant and factory chimneys, removing fly ash before the gas reaches the open air, so (A) outdoor air pollution is the usual textbook answer.
Answer: (D) straight line
By Boyle's law, at constant temperature PV is constant, so P is proportional to $\frac{1}{V}$ and the graph of P against $\frac{1}{V}$ is a straight line through the origin; a real gas follows this closely at low pressure. The hyperbola is the shape of P plotted against V itself, which makes (A) the tempting wrong choice.
Answer: (B) Oersted
In 1820 Hans Christian Oersted saw a compass needle deflect near a current-carrying wire, discovering the magnetic effect of current. Faraday later discovered electromagnetic induction, Ampère quantified forces between currents, and Bohr worked on atomic structure.
Answer: (D) Both (B) and (C)
Hepatitis B and hepatitis C viruses spread through infected blood (transfusions, shared needles) and body fluids, so both are blood-borne. Hepatitis A spreads by the faecal–oral route through contaminated food and water, so choosing only (B) or (C) is incomplete.
Answer: (A) Anthracite
Anthracite has the highest carbon content (over 85–90%) and calorific value, and burns with little smoke, so it is the best quality coal. Bituminous coal comes next, then lignite, and peat is the lowest grade.
Answer: (D) Epidolex
Epidiolex, a cannabidiol (CBD) oral solution for rare forms of epilepsy, was approved by the US FDA in 2018 as the first medicine derived from the cannabis plant. Malarone is an antimalarial, Effexor an antidepressant, and absinthium is wormwood.
Answer: (C) 5
The key counts five SKOCH awards for West Bengal in 2021. The state's projects were honoured more than once that year: ease-of-doing-business services such as the Silpasathi single-window portal in August, and the education and tourism departments in November, so the total depends on which announcements are counted. Note: the widely reported announcement of August 2021 was of four awards (one platinum, one gold and two silver), so (B) 4 is the figure most current-affairs sources give.
No option is correct as printed — this question is disputed. WBPSC awarded the mark to all candidates: no clearly correct option — Madhya Pradesh leads by bamboo area (ISFR) and is not listed, and sources differ between Assam and Arunachal Pradesh.
Answer as of 2023 — this may have changed since.
Sources disagree on this: the India State of Forest Report puts Madhya Pradesh first by bamboo-bearing area, which is not an option, while Assam and Arunachal Pradesh are each cited as leading producers in different sources. With no clearly correct option, the Commission awarded the mark to all candidates.
Answer: (C) Colaba
Old Woman's Island, also called Little Colaba, was one of the seven islands of Bombay and is now part of the Colaba area. Parel, Worli and Mazagaon were separate islands of the original seven.
Answer: (C) Asphalt
Fresh asphalt reflects only about 4–12% of sunlight, the lowest albedo among these surfaces. Forests reflect slightly more, bare soil more still, and fresh snow reflects up to about 90%.
Answer: (D) Duare Sarkar
West Bengal's Duare Sarkar ('Government at the doorstep') outreach programme won a Digital India Award for delivering many state services through camps and an online portal. Swasthya Sathi (health cover), Shilpa Sathi (industry single window) and Rupashree (marriage grant) were not the awarded scheme here.
Answer: (B) DNA fingerprinting
Sir Alec Jeffreys developed DNA fingerprinting in 1984 at the University of Leicester, using variable repeat sequences in DNA. DNA sequencing is linked with Sanger, and site-directed mutagenesis with Michael Smith.
Answer: (C) Urn-shaped
A declining population has fewer young than middle-aged people, giving a narrow base and an urn shape. A triangular pyramid shows an expanding population and a bell shape a stable one.
Answer: (B) Lotic
Lotic ecosystems are those of running water such as rivers and streams. Lentic ecosystems are still waters like ponds and lakes, while benthic and pelagic refer to the bottom zone and the open-water zone of a water body.
Answer: (A) Sara
Emirates introduced 'Sara', billed as the world's first robotic check-in assistant, at its City Check-In and Travel Store in Dubai's financial district (DIFC) in 2023. Siri is Apple's voice assistant, and Kiwi and Rini are not Emirates products.
Answer: (C) Vyom mitra
Vyommitra is ISRO's half-humanoid female robot meant to fly on uncrewed test flights of the Gaganyaan human spaceflight programme. The other names are made-up variations.
Answer: (A) Rio
The UN Conference on Environment and Development (the Earth Summit) was held in Rio de Janeiro in 1992, producing Agenda 21. Stockholm hosted the 1972 UN Conference on the Human Environment, the tempting wrong option.
Answer: (D) uranium deposits.
Jaduguda in East Singhbhum, Jharkhand, has India's first uranium mine, run by the Uranium Corporation of India since 1967. Jharkhand also has iron ore, mica and some gold, but Jaduguda is known for uranium.
Answer: (C) Instantaneous speed
A speedometer shows how fast the car is moving at each moment, which is instantaneous speed. It does not show direction, so it is not velocity, and it does not average over a trip.
Answer: (D) All of the above
Industrial robots are used to reduce labour needs, raise productivity through consistent fast work, and run machines more evenly so they last longer. Since all three are stated aims, (D) is the answer rather than any single one.
No option is correct as printed — this question is disputed. WBPSC awarded the mark to all candidates: two correct options — India uses both AM (MW/SW) and FM for radio broadcasting.
Radio broadcasting in India uses both amplitude modulation (All India Radio's medium- and short-wave services) and frequency modulation (FM stations), so (A) and (B) are both correct. The Commission therefore awarded the mark to all candidates.
Answer: (D) Panna
Answer as of 2023 — this may have changed since.
Panna in Madhya Pradesh, notified in 2011 and added to UNESCO's network in 2020, was the most recently declared of India's 18 biosphere reserves at the time of the exam. Nilgiri (1986) was the first, and Gulf of Mannar and Great Nicobar date from 1989.
Answer: (C) C. Elegans
Andrew Fire and Craig Mello won the 2006 Nobel Prize in Physiology or Medicine for discovering RNA interference in the nematode worm Caenorhabditis elegans. Drosophila, Arabidopsis and fission yeast are other model organisms, not the one used in that work.
Answer: (B) Bernoulli's theorem
In a sprayer, fast-moving air over the top of a tube lowers the pressure there (Bernoulli's theorem), so the liquid is pushed up the tube and broken into droplets. Stokes' law concerns viscous drag, Jurin's law capillary rise, and the virial theorem orbital or molecular energies.
Answer: (B) Radioactive Coesium
Caesium-137, with a half-life of about 30 years, was the main radioactive metal released and spread over Europe by the 1986 Chernobyl accident, and it is responsible for the long-term contamination of the exclusion zone. Uranium was the reactor fuel, but it is caesium that is linked with the accident's lasting damage; plutonium and polonium were not the main contaminants.
Answer: (B) Hockey
The Sultan Azlan Shah Cup is an international men's field hockey tournament held annually in Malaysia since 1983. It is not a badminton, table tennis or golf event.
Answer: (D) both (B) and (C)
Food spoils mainly through the growth of bacteria and moulds (fungi), and low temperature slows the growth and enzyme activity of both. Viruses do not multiply in food, so (A) is wrong, and choosing only (B) or (C) leaves out the other.
Answer: (A) Madhya Pradesh
Kuno National Park is in Sheopur district of Madhya Pradesh and became home to the cheetahs brought from Namibia and South Africa in 2022–23. It was once proposed for Asiatic lions from Gujarat, which makes (C) a tempting wrong option.
No option is correct as printed — this question is disputed. WBPSC awarded the mark to all candidates: ambiguous — sources date India's first paper mill to Serampore (1812/1830s) or Bally (1867), so no option is clearly correct.
The date depends on what counts as the 'first' mill: William Carey's mission at Serampore began making paper around 1812 and installed a steam-driven machine in the 1830s, while the first modern paper mill is usually dated to Bally, near Calcutta, in 1867. Since no option is unambiguously correct, the Commission awarded the mark to all candidates.
Answer: (C) RH 300
ISRO's Rohini RH-300 Mk II is a sounding rocket used for upper-atmosphere studies, launched from Thumba. Agni-IV and BrahMos-II are defence missiles, not sounding rockets, and 'Car to Sat' is not a rocket.
Answer: (D) Proline
The fluid-mosaic cell membrane is a phospholipid bilayer containing cholesterol, proteins and glycolipids. Proline is a free amino acid; it is found inside proteins but is not itself a membrane constituent.
Answer: (D) Rajatarangini
Kalhana wrote the Rajatarangini (c. 1148 CE), a verse chronicle of the kings of Kashmir. Harshacharita is by Banabhatta, Arthashastra by Kautilya, and Indika by Megasthenes.
Answer: (A) Leopold
The title points to 'The Land Ethic', Aldo Leopold's famous essay in A Sand County Almanac (1949), which argued that ethics should extend to soil, water, plants and animals. Rachel Carson wrote Silent Spring, Garrett Hardin 'The Tragedy of the Commons', and Lynn White 'The Historical Roots of Our Ecologic Crisis'.
Answer: (B) Intra-pulmonary pressure.
The pressure of the air inside the lungs is called intrapulmonary pressure; it falls below atmospheric pressure during inspiration and rises above it during expiration. Interstitial pressure is the pressure of tissue fluid, and 'inter-pulmonary' is not a standard term. Alveolar pressure describes the air pressure in the alveoli specifically, while intrapulmonary pressure is the standard name for the pressure within the lungs as a whole.
Answer: (C) Wrestling
Pehlwani (kushti) is the traditional wrestling of the Indian subcontinent, practised in akharas on earthen pits. It has no connection with boxing, football or badminton.
Answer: (B) Assam
Asom Baibhav, Asom Saurav and Asom Gaurav are the three tiers of civilian awards instituted by the Assam government in 2021, Asom Baibhav being the highest. Odisha, Tamil Nadu and Jharkhand have different names for their state honours.
Answer: (A) O$_3$
Ozone is a resonance hybrid of two equivalent structures, so its π electrons are spread over all three oxygen atoms (a 3-centre, 4-electron π system), and both O–O bonds are equal. In CO, HCN and CO$_2$ the π bonds are described as localised between particular atoms.
Answer: (D) Steel
In physics, elasticity means resistance to deformation and the ability to recover, measured by Young's modulus, and steel's (about 200 GPa) is far higher than copper's and vastly higher than rubber's. Rubber stretches easily, which makes it the tempting wrong answer, but that means it is less elastic in this sense.
Answer: (B) National Development Council
The Rashtriya Krishi Vikas Yojana was launched in 2007 following a resolution of the National Development Council to raise agricultural growth to 4%. ICAR is a research body, SBI a bank, and state research boards did not launch the scheme.
Answer: (C) the field between the plates.
The energy of a charged capacitor, $\frac{1}{2}CV^2$, is stored in the electric field between its plates, with energy density $\frac{1}{2}\varepsilon_0 E^2$. It is not stored in the charges themselves, and the fringe field at the edges holds only a small part.
Answer: (B) Ricky Kej
Answer as of 2023 — this may have changed since.
Bengaluru-based composer Ricky Kej won his third Grammy in 2023 for the album Divine Tides, making him the only living Indian with three. A. R. Rahman has two Grammys, and Resul Pookutty won an Oscar, not a Grammy.
Answer: (A) 1
Global warming potential compares the heat trapped by a gas with that trapped by the same mass of CO$_2$, so CO$_2$ is the reference with a GWP of exactly 1. Methane and other gases are expressed as multiples of it.
Answer: (A) Digha
The noon sun is overhead twice a year only at places between the Tropics, and Digha (about 21.6° N) lies south of the Tropic of Cancer (23.5° N). Patna, Kanpur and Delhi are all north of the Tropic, so the noon sun is never directly overhead there.
Answer: (C) Bacitracin
Bacitracin is produced by the bacterium Bacillus subtilis (licheniformis). Penicillin comes from the fungus Penicillium, while chloramphenicol and streptomycin come from Streptomyces, the actinomycetes that older textbooks treat separately from true bacteria.
No option is correct as printed — this question is disputed. WBPSC awarded the mark to all candidates: more than one option defensible — boron is associated with both bone health (D) and brain function (C).
Boron is a trace element linked to bone health through its effect on calcium, magnesium and vitamin D metabolism, and it has also been linked to brain function. With more than one option defensible and no settled single answer, the Commission awarded the mark to all candidates.
Answer: (D) Arunachal Pradesh
Among the states listed, Arunachal Pradesh has by far the longest border with China, about 1,126 km along the McMahon Line. Sikkim, Uttarakhand and Himachal Pradesh have much shorter China borders. (The Union Territory of Ladakh, not a state, has the longest stretch overall.)
Answer: (D) peak voltage for A.C. is much larger than 220 volt.
220 V is the rms value of mains AC, and its peak value is $220\sqrt{2} \approx 311$ V, so the body is exposed to much higher instantaneous voltage than with 220 V DC. The 'attracts/repels' options are not physics.
Answer: (D) 10$^{-13}$m
The X-unit, used for X-ray and gamma-ray wavelengths, is about $1.002 \times 10^{-13}$ metre. $10^{-10}$ m is the angstrom, $10^{-12}$ m the picometre and $10^{-15}$ m the fermi.
Answer: (C) Chalk powder and water mixture
Chalk powder in water forms a suspension (with colloidal-size particles) large enough to scatter a beam of light, showing the Tyndall effect. Sugar, potash alum and potassium permanganate dissolve to form true solutions whose particles are too small to scatter light.
Answer: (C) 1973
The first Women's Cricket World Cup was held in England in 1973, two years before the first men's World Cup, and was won by England. The other years are wrong.
Answer: (C) Kisan Kanya
Kisan Kanya (1937), produced by Ardeshir Irani, was the first indigenously made colour film in India. Alam Ara (1931) was the first talkie, and Pather Panchali and Devdas were black-and-white films.
Answer: (B) UK
Big Ben is the great bell (and popularly the clock tower, now the Elizabeth Tower) of the Palace of Westminster in London, United Kingdom. It is not in the USA, Australia or France.
Answer: (B) 57%
Answer as of 2023 — this may have changed since.
In 2023 thermal power stations (mainly coal and lignite, with some gas and diesel) made up about 57% of India's installed electricity capacity, as reported by the Central Electricity Authority. 50% is roughly coal's share alone, and 64% overstates the thermal share of capacity at that time.
Answer: (B) Lakshadweep
India's ocean-thermal plant, built by the National Institute of Ocean Technology, is at Kavaratti in Lakshadweep, where it uses the warm-surface and cold-deep sea water difference to run a desalination plant. Plans for the Andaman and Nicobar Islands and Tamil Nadu coast have not produced a working plant, and Gujarat and Odisha do not host one.
Answer: (B) Bhotia
The Bhotias of the high Himalayan valleys of Uttarakhand are traditionally transhumant sheep and goat herders and wool traders. The Tharus and Bokshas are agriculturists of the Terai, and the Rajis are forest dwellers.
Answer: (D) vaccines
Animal cell cultures are used above all to grow viruses for vaccines such as polio, rabies, measles and influenza. Insulin is mostly made in recombinant bacteria or yeast, and interferons are a smaller application.
Answer: (A) high voltage and low current.
Power loss in transmission lines is $I^2R$, so power is sent at very high voltage, which makes the current low for the same power and cuts the heating loss. Step-up transformers raise the voltage at the station and step-down transformers lower it near consumers.
Answer: (C) Bordoisila
In Assam the violent pre-monsoon Nor'westers are called Bordoisila, and they help tea and jute crops. Kalbaisakhi is the Bengal name, mango showers fall in Kerala and Karnataka, blossom showers help coffee in Karnataka, and Andhi is the dust storm of north-west India.
Answer: (D) Vit D$_3$
Ultraviolet-B rays in sunlight convert 7-dehydrocholesterol in the skin into vitamin D$_3$ (cholecalciferol). Vitamins B$_1$, B$_6$ and C must come from food.
Answer: (C) Industry
Answer as of 2023 — this may have changed since.
Industry is the largest consumer of commercial energy (coal, oil, gas and electricity) in India, using roughly half of the total. Transport, households and agriculture each use smaller shares.
Answer: (D) Jammu & Kashmir
In February 2023 the Geological Survey of India reported inferred lithium resources of about 5.9 million tonnes at Salal-Haimana in Reasi district, Jammu & Kashmir. Ladakh, Punjab and Gujarat were not the site of that find.
Answer: (C) 1919
The Rowlatt Act, allowing detention without trial, was passed in March 1919 and led to Gandhi's Rowlatt Satyagraha and the Jallianwala Bagh massacre. 1905 is the year of the Partition of Bengal, and 1913 and 1925 are unrelated.
Answer: (D) Lichen
Reindeer moss (Cladonia rangiferina) is not a moss at all but a lichen, a partnership of a fungus and an alga, and is a key winter food of reindeer. Despite its name it is not a bryophyte, and it is neither an alga nor a fungus alone.
Answer: (A) Haeckel
The German biologist Ernst Haeckel coined the term 'ecology' (Oekologie) in 1866. Tansley coined 'ecosystem', Odum is called the father of modern ecology, and Darwin proposed natural selection.
Answer: (A) Hydrogen gas discharge lamp
Hydrogen (or deuterium) discharge lamps give a continuous ultraviolet spectrum and are the standard UV source in spectrophotometers. A Nernst filament is an infrared source, a klystron produces microwaves, and an RF oscillator produces radio waves.
Answer: (A) Assam
Four Indian states border Myanmar: Arunachal Pradesh, Nagaland, Manipur and Mizoram. Assam has no border with Myanmar.
Answer: (C) Intestine
Secretin is made by S cells of the duodenum (small intestine) when acidic chyme arrives, and it stimulates the pancreas to release bicarbonate. The pancreas responds to secretin but does not produce it, which makes (D) the tempting wrong answer.
Answer: (B) atomic energy reactor.
A nuclear reactor uses control rods and moderators to keep the fission chain reaction steady, which is a controlled chain reaction. An atom bomb uses an uncontrolled chain reaction, and the Sun's core runs on fusion.
Answer: (C) Coliform
Coliform bacteria are the standard indicator of faecal contamination, so their absence is used to certify drinking water as pure. Dissolved CO$_2$ is harmless, CO is not a water-quality test, and Enterobacter is just one genus within the coliform group.
Answer: (C) 50 Hz
India's mains supply is 230 V (often quoted as 220 V) at 50 Hz. 60 Hz is used in the USA and some other countries, and 220 is the voltage, not the frequency.
Answer: (A) Purnima Devi Barman
Assamese wildlife biologist Purnima Devi Barman received the UNEP Champions of the Earth award in 2022 for protecting the greater adjutant stork through her 'Hargila Army' of women. Narendra Modi received the award in 2018, which makes (B) the tempting wrong option.
Answer: (C) Rich Like Us
Nayantara Sahgal won the Sahitya Akademi Award for English in 1986 for her novel Rich Like Us, set during the Emergency. A Time to be Happy and The Day in Shadow are her earlier novels that did not win it.
Answer: (C) Ramachandra Guha
Historian Ramachandra Guha wrote India After Gandhi: The History of the World's Largest Democracy (2007). Romila Thapar writes on ancient Indian history, and the other names are not its author.
Answer: (B) Tobacco
The first transgenic plant was tobacco, engineered in 1983 to carry an antibiotic-resistance gene using Agrobacterium. Transgenic rice, maize and Bt cotton came later.
Answer: (C) Isobutane
Domestic refrigerators increasingly use isobutane (R-600a), a hydrocarbon refrigerant with no ozone-depletion potential and very low global warming potential, in place of the HFC R-134a. Normal butane is not the standard choice, and toluene and nitrobenzene are liquids unsuited as refrigerants.
Answer: (A) Bimbisara
Bimbisara (c. 544 BCE) is regarded as the founder of the Haryanka dynasty of Magadha, with his capital at Rajagriha. Ajatashatru was his son and successor, Harshavardhana ruled in the 7th century CE, and Dhanananda was the last Nanda king.
Answer: (D) Radio active elements
The International Atomic Energy Agency, based in Vienna, promotes the safe and peaceful use of nuclear energy and sets standards on radiation and radioactive-waste safety. Heavy metals, hydrocarbons and plastics fall outside its mandate.
Answer: (A) Seleucas Nicator
After his treaty with Chandragupta Maurya (c. 303 BCE), Seleucus Nicator sent Megasthenes as ambassador to Pataliputra, where he wrote the Indika. Antiochus sent Deimachos to Bindusara's court, and Ptolemy II sent Dionysius.
Answer: (B) CO$_2$
Carbaminohaemoglobin forms when carbon dioxide binds to the amino groups of haemoglobin, carrying about 20–25% of the CO$_2$ in blood. Carbon monoxide forms carboxyhaemoglobin instead, which makes (A) the tempting wrong option.
Answer: (A) Ministry of Home Affairs
The National Disaster Response Force, set up under the Disaster Management Act 2005, works under the Ministry of Home Affairs and is made up of battalions drawn from the central armed police forces. The other ministries do not control it.
Answer: (C) Polarisation
Polarisation is possible only for transverse waves such as light; sound in air is a longitudinal wave and cannot be polarised. Reflection, interference and diffraction occur for both sound and light.
Answer: (B) increase.
A non-volatile solute lowers the vapour pressure of water, so a higher temperature is needed to reach atmospheric pressure, raising the boiling point (elevation of boiling point, a colligative property). This is why salted water boils slightly above 100 °C.
Answer: (B) Frequency
Frequency is fixed by the source, so it stays the same when light passes into another medium. Speed and wavelength both change ($v = f\lambda$), and amplitude usually drops because some light is reflected at the boundary.
Answer: (D) 6
In Champion and Seth's classification, India's 16 forest type groups fall under six major groups: moist tropical, dry tropical, montane subtropical, montane temperate, sub-alpine and alpine. 3, 4 or 5 major groups do not match this scheme.
Answer: (B) Gujarat
Answer as of 2023 — this may have changed since.
In 2023 Gujarat overtook Tamil Nadu to become the state with the largest installed wind power capacity in India, at a little over 10 GW. Tamil Nadu led for many years, which makes (C) the tempting wrong option; Karnataka is third and Kerala has little wind capacity.
Answer: (B) 15°C
With its albedo of about 0.3 and the natural greenhouse effect, Earth's average surface temperature settles at about 15 °C. Without the greenhouse effect it would be about −18 °C, and 10, 20 or 25 °C do not match the accepted global mean.
Answer: (C) Gora
Gora (1910) is one of Rabindranath Tagore's major novels, about identity and nationalism. Durgeshnandini is by Bankim Chandra Chattopadhyay and Ganadevata by Tarashankar Bandyopadhyay.
Answer: (D) APSARA
Apsara, a swimming-pool type research reactor at Trombay, went critical on 4 August 1956 and was India's and Asia's first nuclear reactor. Rambha, Menaka and Urvasi are not names of Indian reactors.
Answer: (B) Odilor habdins
Odilorhabdins are a new class of antibiotics produced by Xenorhabdus bacteria that live in soil nematodes; they act on the ribosome and are effective against drug-resistant bacteria. The other names are made-up variations of this word.
No option is correct as printed — this question is disputed. WBPSC awarded the mark to all candidates: question is imprecise — dung biogas is about 50–75% methane, so (C) 50% and (D) 60% are both defensible.
Cow dung itself has no fixed methane content; it is the biogas produced from it that is mostly methane, quoted variously as 50–75% (commonly about 55–65%). With more than one option defensible, the Commission awarded the mark to all candidates.
Answer: (C) bioremediation.
Bioremediation is the use of living organisms, mainly microbes, to break down pollutants such as oil spills into harmless products. Nanoremediation uses nanoparticles, not living organisms, and 'microremediation' is not the standard term.
No option is correct as printed — this question is disputed. WBPSC awarded the mark to all candidates: launcher was LVM3 (formerly GSLV Mk III); (C) is the old name and (B) 'LVSM' appears to be a misprint of LVM3, so two options are arguable.
Chandrayaan-3 was launched on 14 July 2023 by LVM3-M4, the rocket formerly called GSLV Mk III. Option (C) gives the old name and (B) looks like a misprint of LVM3, so more than one option could be marked correct, and the Commission awarded the mark to all candidates.
Answer: (B) Ergosterol
Ergosterol is the sterol of fungal cell membranes (and the target of antifungal drugs); animal membranes use cholesterol instead. Phospholipids form the bilayer, and oligosaccharides attached to lipids and proteins form the cell coat, so both are present in animal membranes.
Answer: (A) 261 BC
Ashoka's Kalinga war took place around 261 BC, about eight years after his coronation, as recorded in his Rock Edict XIII. Its bloodshed led him to embrace Buddhism; the other years do not match.
Answer: (B) Malaria
Artemisinin, extracted from sweet wormwood (Artemisia annua) by Tu Youyou, is the basis of artemisinin-combination therapy for malaria, especially P. falciparum. Dengue is viral, while typhoid and pertussis are bacterial and treated with other drugs.
Answer: (C) Frequency
A transformer changes voltage and current between its windings but cannot change the frequency of the AC, which is set by the supply. Current density changes along with the current.
Answer: (D) Capillary water.
Capillary water, held in the small soil pores against gravity, is the main water available to plant roots. Gravitational water drains away quickly, hygroscopic water is held too tightly on soil particles, and chemically combined water is locked in minerals.
Answer: (A) Alama Ara
Alam Ara (1931), directed by Ardeshir Irani, was India's first sound film. Raja Harishchandra (1913) was the first Indian silent feature film, and Pundalik (1912) was an earlier silent film.
Answer: (A) Sunil Khilnani
The Idea of India (1997) was written by political scientist Sunil Khilnani. Kiran Nagarkar is a novelist (Cuckold) and Shiv K. Kumar a poet, neither of whom wrote it.
Answer: (A) 10 Km
The troposphere is the lowest layer of the atmosphere, and its top, the tropopause, is commonly taken as about 10 km above the surface in middle latitudes. Its height varies with latitude and season, falling to about 8 km over the poles. Note: the troposphere is deepest over the equator, reaching about 16–18 km, so for its 'maximum' height (D) 16.8 km is the closer figure.
Answer: (D) Cricket
The Friends Provident Trophy was the name of English county cricket's one-day knockout cup from 2007 to 2009, sponsored by the insurer Friends Provident. It was not a football, volleyball or squash event.
