Which is the largest flightless bird?
Answer: D
The ostrich is the largest flightless bird - up to 2.7 m tall and 150 kg.
It is also the fastest running bird, at about 70 km/h. The emu is next in size, and the kiwi and the smaller penguins are much smaller.
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One kilometre is equal to how many miles?
Answer: D
One kilometre is about 0.62 miles.
\[ 1\ \mathrm{km} = \frac{1}{1.609} \approx 0.621\ \mathrm{mile} \]
The mile is 1.609 km, so the two conversions are reciprocals of each other.
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Crude petroleum is refined by the use of
Answer: B
Sulphuric acid is used in refining crude petroleum, in the treating stages that remove sulphur compounds, unsaturated hydrocarbons and gums from the distilled fractions.
The separation of the crude into fractions is done by distillation; the acid treatment is what cleans those fractions up afterwards.
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Why does a corked bottle filled with water break when frozen?
Answer: B
A corked bottle of water bursts when frozen because water expands as it freezes, by about nine per cent.
Ice has an open hexagonal structure held by hydrogen bonds, which takes up more room than the liquid. That is also why ice floats, and why water pipes burst in a hard winter.
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Brass is an alloy of?
Answer: C
Brass is an alloy of copper and zinc, typically about 70 per cent copper to 30 per cent zinc.
It is harder than copper, easily machined and cast, and resists corrosion. Bronze, by contrast, is copper with tin.
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Suppose if we measure the time lapse between the two Sunsets by sitting in the beach, from this we can estimate
Answer: C
Timing the interval between two sunsets - one seen lying down on the beach and the second after standing up - gives the radius of the earth.
Raising the eye by a known height lets you see a little further over the curve, and the extra delay before the sun sets again depends on how sharply the surface curves. The geometry then yields the earth's radius.
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Bell metal is an alloy of
Answer: D
Bell metal is an alloy of copper and tin, roughly 78 to 22 - a bronze with unusually high tin content.
The extra tin makes it hard, brittle and highly resonant, so a bell rings for a long time after being struck.
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The stimulant present in Tea is -
Answer: C
The stimulant in tea is caffeine - about 20 to 60 mg in a cup, roughly half that of coffee.
Tannins give tea its astringency and colour but are not stimulants. The caffeine in tea is sometimes called theine, but it is the same compound.
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Which of the following is NOT a kharif crop?
Answer: D
Barley is not a kharif crop - it is a rabi crop, sown in October and November and harvested in March.
Rice, cotton and bajra are kharif crops, sown with the arrival of the south-west monsoon in June and July and harvested in September and October.
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Potassium nitrate is used in?
Answer: A
Potassium nitrate is used as a fertiliser. It supplies both potassium and nitrogen, and unlike most nitrogen fertilisers it contains no chloride, so it suits salt-sensitive crops such as tobacco, citrus and potato.
Its nitrogen is already in the nitrate form plants take up directly. The same compound, saltpetre, is also the oxidiser in gunpowder.
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