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Physical Science

266)The age of the earth can be estimated by
carbon dating atomic clock
uranium dating biological clock
Answer :

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
Answer :

268)The process of joining two hydrogen atoms and forming a helium atom with emision of energy is called
fission fusion
implosion trasnmutation
Answer :

269)In which of the followng fission occurs
nuclear reactors chemical reactors
hydrogen bomb the sun
Answer :

270)Which one of the is enriched Uranium?
Uranium-233 Uranium-235
Uranium-238 Uranium-239
Answer :

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
Answer :

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
Answer :

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
Answer :

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
Answer :

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
Answer :

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