Who proposed the wave theory of light?
Answer: B
The wave theory of light was proposed by Christiaan Huygens in 1678.
It explained reflection and refraction as well as Newton's rival corpuscular theory, but was only accepted after Young's double-slit experiment in 1801 demonstrated interference, which particles cannot produce.
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BACK TO VILLAGES slogan was given by:
Answer: B
The slogan Back to the Villages is associated with Mao Zedong, whose revolution was built on the peasantry rather than the urban working class.
The strategy of encircling the cities from the countryside was the distinctive feature of Chinese communism, and later movements sent students and cadres to the villages to learn from the peasants.
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Old-written material, which cannot be read easily can be read by?
Answer: A
Faded old writing can be read under infrared light. Different inks and the paper beneath them absorb and reflect infrared differently, so the writing shows up in an infrared photograph even where it is invisible to the eye.
The technique is standard in manuscript study and in forensic document examination.
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Which layer protects earth from harmful rays of the Sun?
Answer: B
The ozone layer, in the stratosphere between about 15 and 35 km, shields the earth from the sun's harmful ultraviolet radiation.
Ozone absorbs almost all UV-C and most UV-B, which would otherwise cause skin cancer, cataracts and damage to crops and plankton. Absorbing that energy is also what warms the stratosphere.
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Which amongst the following country do not have cryogenic engine technique?
Answer: D
Canada is the country listed without cryogenic engine technology.
Only a handful of nations have mastered it - the United States, Russia, France, Japan, China and India. India's first indigenous cryogenic stage flew successfully on GSLV-D5 in January 2014.
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The variety of coal in which the deposit contains recognizable traces of the original plant material is
Answer: D
Peat still shows recognisable traces of the plants it formed from - leaves, twigs and roots are often visible in it.
It is the first stage of coal formation, with only about 25 to 35 per cent carbon. With increasing pressure and time it becomes lignite, then bituminous coal, then anthracite, and all plant structure is lost.
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The first synthetic fibre made by man was ____ ?
Answer: D
Nylon was the first fully synthetic fibre, developed by Wallace Carothers at DuPont and put on sale in 1938.
It is built from small molecules rather than from a natural polymer. Rayon came earlier but is regenerated cellulose, so it is not fully synthetic.
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'Bar' is the unit of
Answer: C
The bar measures atmospheric pressure. One bar is 105 pascals, very close to the average pressure at sea level, which is 1.013 bar.
Meteorologists usually work in millibars or the identical hectopascals, so standard sea-level pressure is 1013 mb.
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Which of the following is the lightest metal ?
Answer: B
Lithium is the lightest metal, with a density of 0.53 g/cm³ - about half that of water, so it floats.
It is also the lightest solid element of any kind. Its low weight and high electrochemical potential are what make lithium-ion batteries so effective.
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Pollen grains of flowers in which pollination takes place by insects are:
Answer: D
Insect-pollinated flowers have pollen that is rough and sticky, often with spines or a sticky coating, so that it clings to the visiting insect's body.
Wind-pollinated pollen is the opposite: small, smooth, dry and light, produced in enormous quantity so that a little of it reaches a stigma by chance.
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