226 .A glass container cracks when very hot tea is poured into it. A probable reason for this is the
A.  low thermal conductivity of glass
B.  high thermal conductivity of glass
C.  low specific heat of glass
D.  none of these
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227 .Which one among the following is responsible for formation of 'Ozone Holes' in the stratosphere?
A.  Benzophye
B.  Hydrocarbons
C.  Chlorofluorocarbons
D.  UV radiation
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228 .A number of images of a candle flame are seen in thick mirror
A.  the first image is the brightest
B.  the second image is the brightest
C.  the last image is the brightest
D.  all images are equally brightest
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229 .Project Tiger, a programme to maintain a viable population of tigers in the country and to chalk out areas for their habitat, was launched in the year
A.  1775
B.  1973
C.  1974
D.  1971
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230 .The temperature of water at the bottom of a waterfall is higher than that at the top because
A.  Water at the bottom has greater potential energy
B.  The surface at the bottom provides heat
C.  Kinetic energy of falling water is converted into heat
D.  falling water absorbs heat from the surroundings
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231 .In a pressure cooker the cooking is fast because
A.  the boiling point of water is raised by the increased pressure inside the cooker
B.  the B.P. of water is lowered by the increased pressue
C.  more steam is available to cook the food at 1000° C
D.  None of these
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232 .Laser light is considered to be coherent because it consists of
A.  many wavelengths
B.  Uncoordinated wavelengths
C.  Coordinated waves of exactly the same wave length
D.  Divergent beams
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233 .Heat is transmitted from higher to lower temperature through actual mass motion of the molecules in
A.  conduction
B.  convection
C.  radiation
D.  all of the above
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234 .Which of the following electromagnetic waves has the longest wavelength?
A.  infrared rays
B.  gamma rays
C.  light rays
D.  ultraviolet rays
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235 .Due to improper /in discriminatedisposal of old and used computers ortheir parts, which of the following arereleased into the environment as e- waste?
1. Beryllim
2. Cadmium
3. Chromium
4. Heptachlor
5. Mercury
6. Lead
7. Plutonium
Select the correct answer using the codesgiven below:

A.  1, 3, 4, 6 and 7 only
B.  1, 2, 3, 5 and 6 only
C.  2, 4, 5 and 7 only
D.  1, 2, 3, 4, 5 6 and 7
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236 .The rapidly growing mass of phytoplankton covering the surface water of lake or pond is known as:
A.  Water pollution
B.  Water hyacinth
C.  Eutrophication
D.  Water bloom
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237 .Light from the sun reaches upon in nearly
A.  8 min.
B.  2 min.
C.  6 min.
D.  4 min.
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238 .Sound waves do not exhibit the phenomenon of
A.  interference
B.  diffraction
C.  refraction
D.  polarization
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239 .Sound travel fastest in
A.  steel
B.  air
C.  water
D.  vaccum
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240 .Mirage is observed in a desert due to the phenomenon of
A.  interference
B.  total reflection
C.  scattering
D.  double refraction
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