Winter rainfall 'Mawat' occurs through -

The correct answer is D, Kanwar Sain. The engineer Kanwar Sain conceived the plan in 1948 of carrying the surplus water of the Sutlej and the Beas into the Thar desert, and the canal was taken up on his design. Work began on 31 March 1958 on what was then called the Rajasthan Canal, which draws water from the Harike barrage below the meeting of the Sutlej and the Beas in Punjab. It was renamed the Indira Gandhi Canal in 1984 and, with its branches, is the longest irrigation canal in India, turning parts of Sriganganagar, Hanumangarh, Bikaner and Jaisalmer into cropland. A is wrong because Mohanlal Sukhadia was a Chief Minister of Rajasthan in whose years the work went ahead. B is wrong because Jawaharlal Nehru was the Prime Minister of the day, not the author of the plan. C is wrong because Jainarayan Vyas was also a Chief Minister. Exam tip: conceived by Kanwar Sain in 1948, work started 1958, renamed 1984.

The correct answer is A, Tube well. Tube wells irrigate the largest share of the net irrigated area of Rajasthan, and groundwater drawn through tube wells and wells together waters the greater part of the state's fields. The reason is the climate: rainfall is low and uncertain over most of the state and perennial rivers are few, so a farmer who wants a second crop has to pump water. This heavy drawing of groundwater has pushed many blocks of Rajasthan into the over-exploited category, which is why drip and sprinkler irrigation are pressed in the state. B is wrong because ponds and tanks serve only small pockets, mostly in the south and south-east. C is wrong because open wells, once the mainstay, now water a much smaller area than tube wells. D is wrong because canals, led by the Indira Gandhi Canal, come second and are limited to the north-west and the Chambal command. Exam tip: in Rajasthan groundwater leads, tube wells first and canals second.

The correct answer is C, 949, 929. Census 2011 put the rural sex ratio at 949 females per thousand males and the urban sex ratio at 929, while the figure for the country as a whole was 943, the highest since 1951. The sex ratio is lower in towns and cities mainly because men move there for work and leave their families behind in the village. Two other numbers from the same census are worth fixing: the child sex ratio in the age group 0 to 6 years fell to 919, the lowest since independence, and Kerala had the best state ratio at 1084 while Haryana had the lowest at 879. A, B and D are wrong because they misstate both halves of the pair; no census has recorded a rural figure of 969, 959 or 939 with the urban figure shown against it. Exam tip: Census 2011 sex ratio, total 943, rural 949, urban 929, child 919.

The correct answer is C, Between 40 degrees S and 50 degrees S latitudes. The Roaring Forties are the strong westerly winds of the southern hemisphere between about 40 and 50 degrees south. They blow with such force because there is almost no land in that belt to slow them down, so sailing ships once used them on the route to Australia. Further south the same westerlies are called the Furious Fifties, between 50 and 60 degrees, and the Shrieking or Screaming Sixties beyond 60 degrees. A is wrong because that belt holds the south-east trade winds and the subtropical high. B is wrong because the matching northern latitudes have large landmasses, so the winds there are weaker and are not given this name. D is wrong because the equatorial belt is the doldrums, a zone of calm and rising air. Exam tip: Roaring Forties 40-50 S, Furious Fifties 50-60 S, Shrieking Sixties beyond 60 S.

The correct answer is B, Europe, Antarctica, South America, North America. Smallest to largest, Europe covers about 10.2 million square kilometres, Antarctica about 14 million, South America about 17.8 million and North America about 24.7 million. The full order of the seven continents from largest to smallest is Asia, Africa, North America, South America, Antarctica, Europe and Australia, and Asia alone takes up about thirty per cent of the land surface. Europe is often called a peninsula of the Eurasian landmass because it is not separated from Asia by sea, while Antarctica, though larger than Europe, is almost wholly covered by ice and has no permanent population. A is wrong because it places Antarctica first, though it is bigger than Europe. C is wrong because it makes Antarctica the largest of the four. D is wrong because South America is bigger than both Europe and Antarctica. Exam tip: learn one chain, Asia, Africa, North America, South America, Antarctica, Europe, Australia.