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Physical Science |
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| 266)The age of the earth can be estimated by | |||
| carbon dating | atomic clock | ||
| uranium dating | biological clock | ||
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| 267)The process of the spliting up of a heavy nucleus into roughly two equal fragments with the emission of energy is called | |||
| fission | fusion | ||
| implosion | transmutation | ||
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| 268)The process of joining two hydrogen atoms and forming a helium atom with emision of energy is called | |||
| fission | fusion | ||
| implosion | trasnmutation | ||
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| 269)In which of the followng fission occurs | |||
| nuclear reactors | chemical reactors | ||
| hydrogen bomb | the sun | ||
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| 270)Which one of the is enriched Uranium? | |||
| Uranium-233 | Uranium-235 | ||
| Uranium-238 | Uranium-239 | ||
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| 271)The function of moderator is nuclear reactor is | |||
| to increase the number fissionable nuclei | to moderate the number of secondary neutrons | ||
| to slow down the secondary neutrons | to control the fission reaction | ||
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| 272)A breeder reactor is that which | |||
| does not require fissionable material at all | uses only heavy water | ||
| produces more fissionable material than it burns | None of these | ||
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| 273)The enormous energy released in an atomic explosion is due to the | |||
| conversion of chemical energy into heat energy | conversion of mass into energy | ||
| conversion of mechanical energy into nuclear energy | conversion of neutrons into protons | ||
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| 274)The process by which energy is generated in the sun is the | |||
| fusion of helium | fusion of hydrogen | ||
| fission of uranium | all of these | ||
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| 275)Which of the following are Einstein's discoveries? | |||
| radio activity and X-ray | photoelectric effect and X- ray | ||
| radio activity and theory of relativity | theory of relativity and photoelectric effect | ||
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| 276)The astronomical unit (AU) is the | |||
| mean distance between the surface of the sun and the surface of the earth | mean distance between the centre of the sun and the centre of the earth | ||
| maximum distance between the sun and the earth | minimum distance between the sun and the earth | ||
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| 277)Constellations appear to change their positions at different times of night because | |||
| the earth rotates about its axis | the constellations move faster than the earth | ||
| the earth and the constellations move in opposite directions | the earth revolves round the sun | ||
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| 278)The star (other than the sun) nearest to the earth is | |||
| Alpha Centauri | Pole star | ||
| Vega | Proxima Centauri | ||
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| 279)The star (other tahn the sun) visible to naked eyes is | |||
| Vega | Pole star | ||
| Alpha Centauri | Proxima Centauri | ||
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| 280)Light from the nearest star(other than the sun) reaches the earth in | |||
| 4.2 hours | 4.2 minutes | ||
| 4.2 years | 4.2 seconds | ||
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